Dew Point Records During Current Heat Wave
July 23, 2011 6:28 AM   Subscribe

The latest heat wave set dew point records at Minneapolis-St. Paul, where the dew point reached 82 degrees on July 19th. Similar dew points in the low 80's were observed at numerous east coast locations on July 22. The highest dew point ever recorded was 95 on July 23, 2003, along the Persian Gulf at Dhahran, Saudi Arabia. You will hear people claim on the most torrid days that the temperature is 100 degrees and the humidity is 100%. That has never happened in the USA as it would require a dew point of 100 degrees. Learn more about the difference between dew point and relative humidity here and here. And this table shows the relationship between air temperature, dew point, and relative humidity.

My southern friends will often claim conditions like "it is 100 degrees with 100% humidity. Or similarly, 90 degrees with 90% humidity. These claims are false, at least here in the USA. Don't get me wrong. I lived in the south. I know how uncomfortable hot and humid days can be, day after day after day. But the numbers associated with those most extreme levels of discomfort are not what many people typically claim. This stems from a lack of understanding of dew point and relative humidity. Here is a simple example. Yesterday at 3:00 PM, Wilmington Delaware had an air temperature of 100 degrees and a dew point of 81 degrees. That means the relative humidity was only 54%. Note that a dew point of 81 is extreme! That is approximately the most humid it ever gets anywhere in the USA at any time of year. The 54% tells us that 100 degree air could actually hold much more moisture. Another way to think about it is that if that 100 degree air was cooled to 81, then relative humidity would rise to 100%. So it is possible to have an air temperature of 81 with 100% humidity. But not an air temperature of 100 with 100% humidity.
posted by Seymour Zamboni (107 comments total)

This post was deleted for the following reason: Poster's Request -- loup



 
Dew point where I live was 82 at 10pm last night which made the heat index 104. I had hoped to get some relief from the heat after the sun set. Nope. It was a soupy mess. No relief in sight. Informative post. Thanks.
posted by futz at 6:39 AM on July 23, 2011


Another tangent off of that is the CAPE. Which is, in layman's terms, the potential for thunderstorms and their severity. Basically, the more humidity in the air, the more energy it takes to warm it up, and thus the more energy it contains. So if Tom Skilling tells you there is a high CAPE number, you know that it's going to be miserable out, thunderstorms are possible, and they will likely be strong/rainy. Last night, at midnight, the CAPE number was 4500 j/kg in Chicago. 6+ inches of rain fell.
posted by gjc at 6:42 AM on July 23, 2011 [1 favorite]


Why'd you have to go and remind me that it's already freakin' hot outside and it's not even 9AM yet? I'm really tired of overnight temps over 80. I think it's been almost a month since we've had any real nighttime relief, although one morning last week the humidity was pretty low so the 81 degrees wasn't too bad.

We would have broken our record for consecutive days over 100 degrees already, but there were two days this month the high was only 97. The average temperature so far this month is 90.3 degrees, over 7 degrees above normal.

Actually, looking at the climatological report from the NWS, we've had many days where it's gotten below 80 at night. I say: "maybe out in a field at the airport 10 meters above the ground!" The bricks on my house are noticeably hot until sometime around 4 in the morning.
posted by wierdo at 7:01 AM on July 23, 2011


Here in Muncie, the dew point has been holding steady in the 75º-78ºF range for days. Relative humidity hit 94% at 5am this morning, when the temp was reasonable-ish 77º. Going outside is like walking along the bottom of a very warm swimming pool.

(FWIW, my currect fave for weather tracking is WeatherSpark.)
posted by Thorzdad at 7:01 AM on July 23, 2011 [1 favorite]


Last night, at midnight, the CAPE number was 4500 j/kg in Chicago. 6+ inches of rain fell.

Where do you find the CAPE number for your area?
posted by swift at 7:01 AM on July 23, 2011


"It's not the heat, it's the dew point."

Try it out on your friends.
posted by kozad at 7:05 AM on July 23, 2011 [2 favorites]


I've lived in Dhahran before and can confirm that walking outside in mid-late September is like stepping into a sauna, my shirt would be instantly drenched. That it holds the record does not surprise me. This is my not surprised face.

Why I continue living in places that are disgustingly hot is probably some kind of quirk I should seek therapy for. I like cold weather, really. Vermont, maybe? Something like that.
posted by empyrean at 7:09 AM on July 23, 2011


Sometime in Jr. High or High School we were taught the concept of Dew Point. (yes, a public school that taught science). It's extremely handy to understand the weather.

Currently the dew point in the Twin Cities is 68, the temperature is 70. Result: Thunderstorms.

Yes, July 19th was bad in the cities with a heat index of 118. However, I really feel for Moorehead, MN, which on that day was the most humid place on earth. They had a dew pont of 87.8 with a heat index of 134 degrees F.
posted by Muddler at 7:14 AM on July 23, 2011


After having lived in Houston for many years, I'm actually enjoying being in Austin where it's still hot as hell but at least not a sauna when I step outside. On the other hand, we've been in drought conditions most of the time I've lived here, which isn't so great either. (I understand Houston is relatively dry right now too, which is both kind of nice to think about in terms of humidity and kind of frightening to think about in terms of local climate.)

tl;dr Humidity makes a huge difference in heat tolerability.
posted by immlass at 7:22 AM on July 23, 2011


Oh, forgot to mention that just in time for the severe weather, today the Cities also have their largest outdoor concert in the cities in 30 years (U2), the Twins have a game in their new dome-less stadium, and the big annual Aquatennial festival fireworks display.

This is apparently the karma we deserve for giving the world Tim Pawlenty and Michele Bachmann
posted by Muddler at 7:22 AM on July 23, 2011 [8 favorites]


I can't make heads or tails of that dang Frankenstein thermometer yous have got in the States.

You should really switch to Celcius for my convenience.
posted by Sys Rq at 7:38 AM on July 23, 2011 [9 favorites]


Some things make it so living in the desert ain't so bad. This is one of those things.

Current dew point here? 44

At our family land in Idaho? 28

All those high 70s across the south just make me cringe.
posted by mr_crash_davis at 7:45 AM on July 23, 2011


Yeah, I'm starting to wonder why we didn't consider this sort of thing when we decided to move from Los Angeles to North Carolina a few years ago. It makes me want to cry that we're not even into August yet.
posted by something something at 8:03 AM on July 23, 2011


Why I continue living in places that are disgustingly hot is probably some kind of quirk I should seek therapy for. I like cold weather, really. Vermont, maybe? Something like that.

Vermont can get pretty damn hot and/or muggy in the summer. Try coastal northern California. It pretty much never gets really cold here, but it rarely gets really hot, either. On those days when the temperature rises into the high 80s or 90s, we know that it won't last more than a couple of days - the Central Valley heats up and the hot air rising pulls a cooling marine layer over San Francisco. Natural air-conditioning! (I feel very lucky to live here, and feel very bad for all my friends on the East coast right now. Stay cool, guys!)
posted by rtha at 8:06 AM on July 23, 2011 [4 favorites]


@mr_crash_davis: I'm in the high 70s southern range. It is cringe-worthy. I feel like I actually have to slow down when I step outside. Like everything about me turns into slow motion because it's too damn hot to move at a normal pace.
posted by persephone's rant at 8:06 AM on July 23, 2011


The current temperature here is 55 F; humidity is 91%; dew point is 52. Unsurprisingly, it's foggy.
posted by rtha at 8:12 AM on July 23, 2011


If you are interested in the relationship between temperature, humidity, and comfort, a great tool is the psychrometric chart. On brief review this link seems to have a good intro into how to read one. Other important factors are CLO and MET, literally factors used to measure the amount of clothing and (metabolic) activity of individuals.
posted by meinvt at 8:20 AM on July 23, 2011 [1 favorite]


Nobody has reported from DC yet because our thermometers have all shattered and the meteorlogists' heads are on pikes out on the mall, the unwitting victims of retaliation against a vengeful sun-god by an increasingly disoriented and savage metropolis. Priests are recommending we pray for death. Over.
posted by Navelgazer at 8:32 AM on July 23, 2011 [26 favorites]


rtha wrote: The current temperature here is 55 F; humidity is 91%; dew point is 52. Unsurprisingly, it's foggy

I would just like to let you know that I hate you. ;)

Seriously, though, I know someone who splits his time between Berkeley and Arkansas. Normally he complains about the constantly too-cool-but-not-quite-cold weather in Berkeley, but these hundred degree days are making him wish he was out west, especially since his Arkansas car doesn't have A/C.
posted by wierdo at 8:34 AM on July 23, 2011


My southern friends will often claim conditions like "it is 100 degrees with 100% humidity. Or similarly, 90 degrees with 90% humidity. These claims are false... the numbers associated with those most extreme levels of discomfort are not what many people typically claim.

Tell me about it. The other day this lady claimed, "It's hotter than 40 Hells out there." It was really only about 34 Hells. Fucking liar.
posted by lost_cause at 8:36 AM on July 23, 2011 [11 favorites]


It's hotter in New Jersey than in Miami right now. Snooki must be disoriented.
posted by RobotVoodooPower at 8:47 AM on July 23, 2011 [3 favorites]


I was contemplating the real-life effects of the seasons in Philadelphia. I can measure it by my ability to get to the drugstore, which is up a steep heel. During most times, I have no problem getting up the hill in my wheelchair.
During Snowmageddon: Uh no, can't do it, as there feet of snow.
During Whatever the Hell you call this ungodly spell of weather: I could do it, but as my core temp would probably be in the low hundreds by the time I get to the drugstore, better not.

I'm a special case, but damn there's a reason why they say heat is the most deadly natural disaster.
posted by angrycat at 8:48 AM on July 23, 2011 [1 favorite]


As a Southerner, allow me to speculate that this heat is the source of the stereotypes about Southerners being lazy.
posted by sonic meat machine at 8:50 AM on July 23, 2011 [10 favorites]




I walked not more than ten feet from my car to my front door and brewed up a steaming batch of balls soup. My sympathies to the Northeast!
posted by Renoroc at 8:59 AM on July 23, 2011


Nobody has reported from DC yet because our thermometers have all shattered and the meteorlogists' heads are on pikes out on the mall, the unwitting victims of retaliation against a vengeful sun-god by an increasingly disoriented and savage metropolis. Priests are recommending we pray for death. Over.

I dunno, I just went biking and it didn't feel that bad. What's it called when your body has become so inured to unpleasant conditions that you don't notice anything anymore?
posted by psoas at 8:59 AM on July 23, 2011


RobotVoodooPower, Snooki is always disoriented.
posted by mr_crash_davis at 9:01 AM on July 23, 2011 [1 favorite]


Yeah. This is pretty much a yearly occurrence in DC. The thing that makes it remarkable, IMO, is that it's been going on for nearly a week with no big thunderstorm to break it up. A few days ago, the nighttime temperature stayed above 90° all night.

...and it looks like it's only going to gradually fade out. It's a bit cooler today than yesterday, and it looks like that trend will gradually continue for the next week until we get back to a more humane temperature. Annoying too, because I really want to go for a run or bike ride.
posted by schmod at 9:03 AM on July 23, 2011 [1 favorite]


Dew point is the only sensible way to measure humidity. The problem with % relative humidity is that it is meaningless without also knowing the temperature, and even then is still pretty hard to interpret.

The Capital Weather Gang (the best weather forecast in the DC area) explains it pretty well:

Dew point      How Humid it Feels
Below 55       Dry (Pleasant)
55-60          Hint of humidity (Still comfortable)
60-65          Moist (Tolerable)
65-70          Sticky (Becoming unpleasant)
70-75          Muggy (Gross)
Above 75       Sultry (Oppressive and unbearable)

posted by exogenous at 9:08 AM on July 23, 2011 [9 favorites]


Whenever y'all wonder why we all tawk soooo slooow in the South, remember this summer. And thank you, air-conditioner-inventioning man. Without A/C, the South would be a third-world country.
posted by thebrokedown at 9:10 AM on July 23, 2011 [7 favorites]


Nobody has reported from DC yet because our thermometers have all shattered and the meteorlogists' heads are on pikes out on the mall, the unwitting victims of retaliation against a vengeful sun-god by an increasingly disoriented and savage metropolis. Priests are recommending we pray for death. Over.

Oh come now, having the worst climate in the continental US is all worth it for those 3 days of cherry blossoms, isn't it?
posted by FelliniBlank at 9:14 AM on July 23, 2011 [1 favorite]


Michigan has had a brief respite yesterday and today with dewpoints in the 67---low 70s range, but during the rest of the week, every time I got out of the air-conditioned car, my glasses immediately fogged up and I was worried about creating my own personal tornado.
posted by FelliniBlank at 9:21 AM on July 23, 2011 [1 favorite]


I like to think our sultry southern weather is responsible for great writers due to heat induced hallucinations.
posted by shimmerglimpse at 9:22 AM on July 23, 2011 [2 favorites]


It's not just how prolonged it is with no thunderstorm to break it. This is the hottest it's been in DC since July 1980. The heat index yesterday was 121ºF.
posted by Navelgazer at 9:22 AM on July 23, 2011


In my location presently it's 93° with a dew point of 80°. Hideous.
posted by sonic meat machine at 9:24 AM on July 23, 2011


I can't make heads or tails of that dang Frankenstein thermometer yous have got in the States.

Handy guide:

More than 100: You gotta be fuckin' kidding me
100: Really damn hot
90: Damn hot
80: Kinda hot
70: Nice
60: Also nice
50: Jacket or sweater, at least if you are a candy-ass.
40: Still a jacket
30: Barely freezing, but that just ain't that cold in the grand scheme of things. Coat and maybe a hat.
20: Coat and hat and gloves. Getting actually cold.
10: Really damn cold.
0: Fuckin-A.
Below zero: You gotta be fuckin' kidding me.
posted by ROU_Xenophobe at 9:25 AM on July 23, 2011 [37 favorites]


In Virginia its powerful hot and the humidity is %110.
posted by TheTingTangTong at 9:29 AM on July 23, 2011 [1 favorite]


Anyone here qualified to answer why there haven't been as many strong thunderstorms (at least in Michigan) as one might ordinarily expect in times of high temperatures? There have been some of those little storms that pop up, but few of the large-scale organized squall lines. The energetics are present; is it a moisture content thing? Or are there other elements that I'm completely missing?

(Also, not to hijack the thread, but if anyone wants to recommend a book that's something like Weather-for-Physical-Scientists-from-other-fields, I'd enjoy it. Or even a 'real' weather textbook that isn't just obsessed with showing off vector calculus.)
posted by kiltedtaco at 9:30 AM on July 23, 2011


I stayed inside for like two days before venturing out yesterday wherein I opened the door and was hit by this oven of air and involuntarily shouted " WHY?"
posted by The Whelk at 9:31 AM on July 23, 2011 [12 favorites]


The air conditioning in my office half gave up this week so even at work it was 80+ inside. It doesn't help that there are 1500 servers running in the test lab that's ten feet from my desk. We had a 1/2 second brownout yesterday afternoon and the sound of all the low-power alarms going off was deafening.
posted by octothorpe at 9:40 AM on July 23, 2011


Handy guide:

nice - and i have to add that in many locales in the states, one will actually see ALL of these if one hangs around long enough - the coldest to hottest i've experienced in s w michigan is -24 to 103
posted by pyramid termite at 9:45 AM on July 23, 2011 [1 favorite]


his Arkansas car doesn't have A/C.

In July? Jesus. Jesus. JESUS. As a veteran of more than a few Arkansas summers, I think I'd rather have salt thrown in my eyes than drive around in one in a car with no air conditioning.
posted by Mr. Bad Example at 9:47 AM on July 23, 2011


The current temperature here is 55 F; humidity is 91%; dew point is 52. Unsurprisingly, it's foggy

I would just like to let you know that I hate you. ;)


Normally this time of year, I'd be complaining about the oppressively grey, windy and chilly weather here in San Francisco. This cold, dull funk means that we often don't see the sun for weeks (at least we don't out here in the Sunset district), and it doesn't let up until late august. I usually get lethargic and depressed in the summer. However, listening to the national weather report is kinda making me love this weather. I will not complain about rocking two layers of polar fleece and wool caps, at least to people outside of NorCal.
posted by echolalia67 at 9:50 AM on July 23, 2011 [1 favorite]


I live in Seattle, where we have had the coldest, wettest summer on record. I've been dressing my kids in their too-small spring clothes for weeks.

I am so. fucking. glad I live here and not in the baking hell that is the rest of the country. the rest of you have my deep and bleeding empathy. I am so sorry. We really need to split the difference over the Rockies, this is not OK.
posted by KathrynT at 9:50 AM on July 23, 2011 [4 favorites]


I had to mow the lawn yesterday. I have zoysia, which keeps growing even when it's been highs above 95 for a week.

I had it all planned out that I was gonna do it in the morning, after checking my work email and making sure my kid had eaten breakfast etc., but before it got too hot.

It was 90 degrees at 8:30 a.m. in my yard yesterday, and the air was so thick with humidity it was like walking into a sauna. By the time I was finished mowing, it was more like 96. By the time I finished watering my poor wilty vegetable garden it was 98. All before noon.

While I was outside I was struck most not by the heat itself but by the silence. No kids were out playing. The squirrels weren't running around chattering. The birds weren't even singing. It was the kind of silence you get after a heavy snowfall.

As a St. Louisan it's a point of pride to mention that I'm used to this kind of heat. But not EVERY DAY FOR A WEEK OR MORE. Ugh.
posted by BlueJae at 9:50 AM on July 23, 2011 [2 favorites]


gingerbeer spent most of this week in DC for work. She said when she stepped out of the terminal at SFO last night to wait for me, all her cells were like "Yay!"

I was in DC in early June for work. I used to live there and I don't miss the weather. The few days I was there for work, temps didn't drop below 90, even at night. I went to bed one night about 11:30, and it was still 96. Horrible.
posted by rtha at 9:50 AM on July 23, 2011


It is currently 94.3 degrees with a dew point of 69 and a heat index of 99. Much nicer than yesterday. I am in a room with 5 beverage coolers and a broken air conditioner. A few feet to my right is a kitchen. The vent above the grill is broken and the heat has nowhere to go. There are storms forecast for later, when they come I will go dance in the street.
posted by furiousxgeorge at 9:56 AM on July 23, 2011 [1 favorite]


immlass, here's what you're missing in Houston: 98.6 degrees, 80 degree dewpoint (average for July is 72), heat index of 120. Kinda miserable, despite being a relatively dry summer.
posted by Houstonian at 9:57 AM on July 23, 2011 [1 favorite]


It is currently 94.3 degrees with a dew point of 69 and a heat index of 99. Much nicer than yesterday.

That is a horrible, crushing pair of sentences.
posted by KathrynT at 9:57 AM on July 23, 2011 [5 favorites]


66ºF right now on its way to 72ºF. The humidity currently 75% but the marine layer is burning off so I suspect the humidity will fall as the sun comes out.

After living in Austin, Vegas and Phoenix, I gotta say I'd take 115ºF in PHX over 100ºF w/any humidity in AUS any day. I remember people in Austin saying how bad it is in Houston but I would always manage to visit on dry days. Then one time I stepped out of my car in in Houston and my sunglasses fogged up and I was hit by the moisture in the air and thought to myself, so THIS is the mugginess people complain about.

The worst most uncomfortable heat/humidity I've ever encountered was in Chicago one summer. It was dreadful. Until I went to Russia a few years ago, Chicago also was the coldest place I've been.
posted by birdherder at 10:02 AM on July 23, 2011 [1 favorite]


It's 92 here, with a dew point of 66, heat index of 96.

We've got a roller derby bout tonight in an arena that is not very well air conditioned.

We're all gonna die.
posted by Lucinda at 10:05 AM on July 23, 2011


I'm off to do this in 2 hours. 99ºF, Dew Point of 74º. 109º Heat Index.

Philly is sounding lovely to me right now.
posted by Navelgazer at 10:12 AM on July 23, 2011


So how did those settlers manage in the 18- & 19-whatevers? Have we somehow lost the genes for resilience over the last two generations?

It's easy for me to talk, here on the Alberta prairies where we almost never have to worry about the humidity, but yesterday at work we had the opposite conversation: how did people survive when it was minus friggin' ahundred in the winter? (I'd agree that heat and humidity are harder to deal with.)

So how did people manage before A/C? There were big cities with no a/c in N. America 100 years ago... Is it "worse" because we're used to a/c? Or is it because we spend so much time in cars nowadays?
posted by sneebler at 10:23 AM on July 23, 2011


San Francisco people: come to the East Bay! It's warmer here.

Everyone else: come to the East Bay! It's cooler here.
posted by madcaptenor at 10:28 AM on July 23, 2011 [4 favorites]


Seriously, though -- people don't realize that humidity is relative -- it's the amount of water in the air divided by the amount it could hold. So they logically think that if there's more water in the air, then the number they hear on the air must be higher. "Relative humidity" is a technical term that shouldn't have made it out to the public. Division is hard, let's go shopping.
posted by madcaptenor at 10:33 AM on July 23, 2011 [1 favorite]


So how did people manage before A/C?

Well for me "Before AC" was two days ago and we managed. I bought a used window unit from a co-worker for $50 since he wanted to get rid of it. We still only use it in the bedroom at night. Out of my 47 years, I've lived with AC for about six of those and I didn't die from it.
posted by octothorpe at 10:34 AM on July 23, 2011 [2 favorites]


I actually don't have AC in my apartment, which doesn't really need it. Oh, trust me that I'd like some right about now, but in general, my place is an English basement with the windows completely covered with vegetation. It keeps cool pretty naturally.
posted by Navelgazer at 10:38 AM on July 23, 2011


Then one time I stepped out of my car in in Houston and my sunglasses fogged up and I was hit by the moisture in the air and thought to myself, so THIS is the mugginess people complain about.

My definition of "humid" is when my glasses fog on indoor-outdoor transitions like that.

(Houstonian, ugh, sorry to hear that. I haven't been checking the heat index here but I now have a new toy in Lion and it tells me "feels like 99" so I'm counting myself lucky. Still waiting to walk until in the morning.)
posted by immlass at 10:39 AM on July 23, 2011


I never understood the humidity readings in the newscasts until I saw a well-informed patient weatherhead talk about the dew point once on the news. Now I never, ever, ever go out in the summertime without checking what the dew point will be first. In California, I didn't give a flying crap what the dew point was -- ever.

Our dew point in Nashville is right now 70 and climbing. It will be in the mid- to upper 90s all day. We haven't had a below-90 day in weeks. It's still only the end of July. My only consolation is cringing at the thought of being in DC or New Orleans right about now.

Oh yeah, with all due respect and love for a wonderful, terrific, beautiful city, here from my sweat-drenched hell: damn you Seattle.

Houstonian: immlass, here's what you're missing in Houston: 98.6 degrees, 80 degree dewpoint (average for July is 72), heat index of 120. Kinda miserable, despite being a relatively dry summer.

That is not kinda miserable. That is sheer unadulterated hell.

echolalia66: This cold, dull funk means that we often don't see the sun for weeks (at least we don't out here in the Sunset district), and it doesn't let up until late august.

Which is exactly what I miss most about living in the Sunset.
posted by blucevalo at 10:39 AM on July 23, 2011


sorry, echolalia67
posted by blucevalo at 10:40 AM on July 23, 2011


Talking to an electrical engineer with xcell energy last night, he said last week the Twin Cities hit new record peak power usages (for the area) every day because of the weather.
posted by edgeways at 10:43 AM on July 23, 2011



Talking to an electrical engineer with xcell energy last night, he said last week the Twin Cities hit new record peak power usages (for the area) every day because of the weather.


That was an extra bit of suck for me: I dread power outages of any kind at work, because they set off a chain of events that is the most tremendous pain an ass has ever known.


I counted myself relatively lucky that everything stayed stable and on.


Then I walked outside into a wall of slime. It was like living in someone's mouth.

ball soup

The entire Twin Cities was awash in 6-8 inches of ball soup last week. There should have been flood warnings, but there are some things meteorologists just don't have words for.


We're fine at present, though, and come the Winter Swearstorms, we will be begging for this.
posted by louche mustachio at 11:03 AM on July 23, 2011


I live in Wisconsin, and we had our break this past thursday, but when I went to work earlier in the week, I got out of my Air Conditioned car, and my glasses instantly fogged up.

I'm so glad it's not as miserable. Today actually looks like an autumn sky, actually.

I'm grateful I work in an Air Conditioned office. I don't know how people handle it without it. Guess I'm soft.
posted by symbioid at 11:09 AM on July 23, 2011


Why I continue living in places that are disgustingly hot is probably some kind of quirk I should seek therapy for. I like cold weather, really. Vermont, maybe? Something like that.

Fairbanks!

Currently 65F (at 10 am), dew point at 52, supposed to get to a high of 79. And sunny. No rain in the forecast.

When I moved up here, a friend said that the summers in Fairbanks make up for the (long, cold) winters. And it's true.

Mind you, there's usually a week or so where it doesn't break -40. And it doesn't get above 0F for most of the winter. But it's still and dry, so it's really not so bad.

I grew up in the Midwest. (my folks are in illinos still). I really feel bad for you all...
posted by leahwrenn at 11:11 AM on July 23, 2011




I just got done riding my bike for 2.5 hours. I'm not sure if that qualifies me for the nuthouse I rode past. It's 99, but the dewpoint is down around 75.

It wasn't a bad ride, really - I didn't even mind the 12mph headwind. What killed me was being blocked from getting home by a pair of trains which forced me to sit *still* for almost ten minutes. Now that made things unpleasant.

Ugh.
posted by notsnot at 11:15 AM on July 23, 2011 [1 favorite]


MetaFilter: awash in 6-8 inches of ball soup.
posted by AsYouKnow Bob at 11:31 AM on July 23, 2011 [1 favorite]


97° and 78° right now, just to prove that tiny spark of life left in me was worthless
posted by sonic meat machine at 11:35 AM on July 23, 2011


I like sonic meat machine's posts, if only because they lend themselves to a narrative of him posting from an undisclosed location in hell.
posted by Navelgazer at 11:53 AM on July 23, 2011 [1 favorite]


So how did people manage before A/C?

I still manage without it in Michigan every day and most nights -- teeny bedroom window unit offset by several dogs. Holy crow, you have no idea how much heat a 12-pound shih tzu can throw off until you sleep next to a couple.

What freaks me out about weather 100 years ago is the clothing. If I had on right now what the average American woman wore, I'd be fucking delirious or dead, and it's only 86 degrees w/64 degree dewpoint.

Or to be out in some South Dakota blizzard in a thin wool coat milking cows? I'm sure people were way hardier and less whiny than we are, but there's only so much the human body can stand despite a cheery outlook.
posted by FelliniBlank at 11:57 AM on July 23, 2011


I am in DC and it sucks.
posted by k8t at 11:59 AM on July 23, 2011


Why do I always feel like apologizing for living in San Diego? (78 degrees, dew point 57.)
posted by SPrintF at 12:07 PM on July 23, 2011


(Also, not to hijack the thread, but if anyone wants to recommend a book that's something like Weather-for-Physical-Scientists-from-other-fields, I'd enjoy it. Or even a 'real' weather textbook that isn't just obsessed with showing off vector calculus.)

Look up your forecast at weather.gov. Near the bottom of the page, there should be a link to their "forecast discussion." In there, the meteorologists explain why they're forecasting what they're forecasting. It can be a bit terse, but with a little Googling/Wikipediaing it can make for a nice education on the processes going on overhead.
posted by penguinicity at 12:38 PM on July 23, 2011 [3 favorites]


It's not just how prolonged it is with no thunderstorm to break it. This is the hottest it's been in DC since July 1980. The heat index yesterday was 121ºF.


I live about 65 miles from DC further down the Potomac and at 5:30 PM while in the grocery store the local radio station announced the heat index was 130. Then they repeated it to let us know we weren't hearing things. It is just ridiculous at this point.

I don't handle normal heat well (screwed up thyroid, disabled, after cancer effects) but, when it gets like this going outside is frightening for me. I have done as little as possible that involves leaving the house. Even in the house, with two AC units running it is not cool enough for me. The AC's can't keep up with it. Last I checked it was 94 and the heat index was only 108, which is a pretty big saving.
posted by SuzySmith at 1:00 PM on July 23, 2011


saving= difference. Trying to do too much at once, here.
posted by SuzySmith at 1:04 PM on July 23, 2011


I don't often feel that people "deserve" to be rich. Except for the person who invented the air conditioner.
posted by SpacemanStix at 1:16 PM on July 23, 2011 [2 favorites]


So how did people manage before A/C? There were big cities with no a/c in N. America 100 years ago... Is it "worse" because we're used to a/c? Or is it because we spend so much time in cars nowadays?

1. they moved slower, and not so much in the worst part of the day.
2. Houses were built when possible with "breezeways" and other cooling-promotion devices
3. There was a thread just this week about how layers of clothing don't necessarily make you hotter, done right.
4. City dwellers had it worst then too; at night, lots of families would sleep on roofs, fire escapes, or even in the parks.
posted by emjaybee at 1:25 PM on July 23, 2011 [2 favorites]




So how did people manage before A/C?

They had more strategies to deal with it. My modern apartment turns into a dank, sweaty armpit once the weather gets above 80F, because it's got no shade and the windows are arranged so that it's imposible to get a cross-breeze. But I've lived in older houses where this kind of weather (80-90F, humid) is perfectly livable.

Also, the reason we're even talking about this weather right now is that it's unusual. People back then had to deal with mind-numbingly hot days, but it wasn't a normal occurrence for it to be this hot, for this long.

They also did other things that we don't do now, for whatever reason. In swamp-like Missouri, a lot of older houses have large covered porches, and families would sleep there instead of inside on the worst days of the year. My grandmother would sometimes sleep out in the yard with her family. Nowadays, someone sleeping in their yard would probably get questioned by the cops.
posted by Kutsuwamushi at 2:07 PM on July 23, 2011


This is why I like the Bay Area. No annoying weather.

(For those on the Celsius scale, this means average temps between 10 and 20 C all year, with record-setting extremes of 5 and 35.)
posted by ryanrs at 2:27 PM on July 23, 2011


Architecture used to be designed to deal with heat: deep eaves, porches that sheltered the walls and windows, open clerestories, and ten or twelve-foot ceilings. Now, we build plastic, hermetically sealed boxes with no relation to the climate and geography that surround them.

My grandmother's house, when I was small, had only a window unit in the living room. The rest of the house was cool because it was shaded by trees, had deep eaves, and a tin roof that reflected a lot of heat.
posted by sonic meat machine at 2:34 PM on July 23, 2011 [1 favorite]


Dew point? Heat index? That's commie talk.
posted by neroli at 2:37 PM on July 23, 2011


Then I walked outside into a wall of slime. It was like living in someone's mouth.

Walking down the street in NYC today was like being trapped with 8.5 million people all simultaneously being crushed between King Kong's testicles.
posted by elizardbits at 3:10 PM on July 23, 2011 [2 favorites]


(in this scenario, King Kong is wearing an unfortunate polyester leisure suit.)
posted by elizardbits at 3:10 PM on July 23, 2011 [1 favorite]


I can't make heads or tails of that dang Frankenstein thermometer yous have got in the States.

ROU_Xenophobe nailed it. But I would like to add: there are 212-32 = 180 degrees between boiling and freezing in our country, vs. 100 between everywhere else.

This really helps in some people's intuition. For instance, 100 degrees here is a mere 38 otherwise. 70 degrees here is 21. A difference of 30 and 17 respectively. So if it were to cool from that hot temperature to that much cooler one, I can quantify it with a bit more feeling: "IT GOT 30 DEGREES COOLER, AWESOME!!!" Compare that with saying "IT GOT 17 DEGREES COOLER, YAY!!!"

OK, so maybe it really does not matter. But it is just a different scale with different contexts behind them. My physics prof lectured on Fahrenheit development, saying that the inventor spoke to the Lord saying "I could find a nice even temperature for freezing and boiling points, but every one I have found for normal body temperature has been in fractions. Why?"

God responded: "Because you're all sinners, imperfect, and undeserving of such an even number."

And so 98.6 is our normal body temp in Fahrenheit.

Lastly: if you need to, just convert, and do it right.
posted by JoeXIII007 at 3:53 PM on July 23, 2011


I always equate heat and humidity with torch songs and jazz. I don't know why. All I know is, I start hearing Marlene Dietrich in my head I know it's about 98.

Handy guide:

Jazz Torch Point                                 How Sultry it Feels

Below 55  Walkin' My Baby Back Home Nat King Cole - Swellness! (Pleasantville)
55-60       Body And Soul Billie Holiday - nice with a hint of sultry
60-65       Why Don't You Do Right? Jessica Rabbit - Toony sultry
65-70       I Wanna Be Loved By You Marilyn Monroe - Corny sultry
70-75       Fever Peggy Lee - Sexy sultry (Torrid)
Above 75   Love For Sale Julie London - Sultry (You gotta be fuckin' kidding me sultry)
posted by Smedleyman at 4:02 PM on July 23, 2011 [6 favorites]


The most brutal one/two punch of heat and humidity I ever experienced was on an overnight drive from Albuquerque to the San Diego Comic Con back in the '80s. We stopped for food + gas in Phoenix just after midnight. The temperature sign in front of the convenience store still read in the high-90s, and the remains of a brief monsoon-season gully-washer was evaporating off the still-warm blacktop parking lot.

Going back through the weather records I'm pretty sure this would have been early on Wednesday 8/5/1987 (SDCC was in early August back then). For a while after midnight that summer rainstorm pushed the humidity readings at Sky Harbor up over 90%, after an official high the previous day of 106º.

I hope I never ever ever experience that particular combination of saturated air and ambient temperature again -- opening the door of the van was like being shoved into an oven where someone had been simultaneously baking a pizza and running a hot shower for half an hour. It was actually difficult to breathe for a minute.

I realize that memory is unreliable and tends to exaggerate, but if the heat index in that particular parking lot at that particular moment was anything under 135ºF (95º air at 80% humidity, which both seem plausible under the specific circumstances) I will eat a jar of bugs.
posted by Lazlo at 4:09 PM on July 23, 2011


Dude, Lazlo, it was like that when I got home from the grocery store JUST NOW. There was a spot shower in my immediate neighborhood that cooled the air from about 104 (not exaggerating -- saw more than one thermometer on the way home) to about 99 according to my car themometer. And when I got out of the car, you could see the steam rising from the ground -- not just from concrete but even from the grass. Or at least, I could see it for a millisecond before my glasses completely fogged over. When I got into the AC in the house the lenses actually dripped water.

Unfortunately, today wasn't the first time I've witnessed that phenomenon.
posted by BlueJae at 4:46 PM on July 23, 2011


Meanwhile, here in Korea, the summer rainy season, usually unbearable, has been much drier and cooler overall than usual. Knock on wood -- so far, anyway.

The climate is most definitely changing all over the place, for whatever reasons one cares to name.
posted by stavrosthewonderchicken at 6:02 PM on July 23, 2011


This has really sucked, I'd take the depths of December/January over this July. It makes me sad.
posted by autoclavicle at 6:18 PM on July 23, 2011


Thanks for posting this Seymour Z. I always have to grit my teeth not to butt into people's conversations in grocery lines or whatever about it being 90-100 percent humidity. Or correct my non-met friends status messages on Facebook.

By the way, the extreme dew points that top 80 F are usually influenced by the evapotranpiration of crops into the atmosphere. Corn is an excellent evapotranspirator, one of the best in fact. Thus, you can see see dew points in the 80s in Iowa during the summer while the Gulf Coast, which is closer to the water, only has dew points in the 70s. The Moorhead, MN observation from last Tuesday was located too close to crops and standing water, and most mets think it wasn't representative.

From way up-thread, swift was asking where you can find CAPE. You can go to the Storm Prediction Center's upper air sounding archive and click on a map. The CAPE will be a number located near the bottom of the chart, in general 1000 J/kg or better will get you storms. However, if the CINH number right beside it is strongly negative, that means that there is a lot of warm air at the mid levels of the atmosphere, which may "cap" and prevent thunderstorm development.

Killtedtaco was asking why Michigan wasn't getting many strong storms despite the juicy air. I haven't looked there specifically, but that's generally the case when there isn't enough wind shear in the atmosphere. Storms will bubble up, but the updraft is then cooled off quickly by the rain generated by the storm and the storm dies in less than an hour. This happens in the tropics all the time. To get the long lived severe storms you need enough wind shear to tilt the storm so the rain cooled air doesn't fall into the warm moist updraft and kill it off too quickly. Instead if there is a tilt to the storm, you have an updraft and downdraft existing together and if there is a very large amount of shear, it can start rotating.
posted by weathergal at 6:20 PM on July 23, 2011 [3 favorites]


"I don't often feel that people "deserve" to be rich. Except for the person who invented the air conditioner.
posted by SpacemanStix"





Carrier stood on the shoulders of a giant. Freakin' Apalachicola.
posted by cookie-k at 7:26 PM on July 23, 2011


If it is any indication as to how hot/humid it is in my area, my houdini pogo stick fence destroyer Hank the dog has decided to cease and desist all efforts to go cavorting even though he has an easy out. He defeated my fence fortifications a week ago (for the 50th time? Not exaggerating) and after escaping once he has decided that AC is his friend. I need to fix the (8ft high, yes 8ft) fence but the swampy heat is keeping us both inside. His last escape lasted maybe 10 minutes before he showed up at the front door with his tongue dragging. I never not fix the fence. It can be 20 below and I fix the damn fence. Fuck this heat and humidity...but wow, what a fence!
posted by futz at 7:52 PM on July 23, 2011 [1 favorite]


For all you that complain about your glasses fogging, I used to work in a meat warehouse. Our "front dock" had to be extra cold, incase a truck came in with a bad reefer, to get the meat back down to temp fast. That front dock, probably 80 yards long, was also what we had to walk down to get out of the building. So I'm walking along, breathing in -5F air, and step outside into wonderful, 95+, 75Fdewpoint St. Louis air.

My *sinuses* fogged up. Like, you know when you're in the pool and get water in your nose and it hurts like a motherfucker? Like that.
posted by notsnot at 7:57 PM on July 23, 2011 [1 favorite]


notsnot, eponyappropriate?
posted by futz at 8:01 PM on July 23, 2011 [2 favorites]


futz- Ha! Brilliant.
posted by notsnot at 8:05 PM on July 23, 2011 [2 favorites]


*humid bow*
posted by futz at 8:11 PM on July 23, 2011


3. There was a thread just this week about how layers of clothing don't necessarily make you hotter, done right.

You know, I was wearing a suit the other day, and I noticed that I didn't seem as hot. Like the jacket kept the sun off me so I wasn't cooking so badly.
posted by gjc at 9:16 PM on July 23, 2011


Meanwhile here in Wellington it's "4.7 C, feels like 0.0 from wind chill". There's gotta be a happy medium...
posted by rodgerd at 10:03 PM on July 23, 2011


Metafilter: "8.5 million people all simultaneously being crushed between King Kong's testicles."
posted by Mitheral at 2:33 AM on July 24, 2011


Carrier stood on the shoulders of a giant.

I once attended a school named for John Gorrie. A school with no air conditioning.
posted by asperity at 5:38 AM on July 24, 2011 [1 favorite]


This morning when I went out, it was 68 with a 68 dewpoint, rather like walking through a tank of lightly chilled gazpacho, only with a large cloud of aggressive deer flies instead of cucumber bits. Then it rained for a few minutes. I love rain.
posted by FelliniBlank at 5:39 AM on July 24, 2011 [2 favorites]


If you're in DC, and see a homeless person who is in obvious distress due to the heat (as I did this morning), please call 1.800.535.7252, and these guys will send someone to make sure that they get a ride to an air-conditioned shelter or cooling center.

And, Jesus Christ. The bystander effect is a fucking horrible side of human nature*. There was a woman lying face-down in a gutter covered with flies at a busy intersection, and nobody did anything. When I got there, I asked a few people at the bus stop how long she'd been lying there, and they all shrugged. Even the cop I flagged down seemed ambivalent.

*And, truth be told, I was tempted to carry on my way myself. After all, somebody else was going to take care of her, right?

posted by schmod at 9:47 AM on July 24, 2011 [1 favorite]


Today it's even hotter. 98°, 78°. 116° heat index.

Why did I move here?
posted by sonic meat machine at 10:20 AM on July 24, 2011


In my no-AC office, in on old industrial building with huge windows, things generally don't get too terrible until later in the afternoon when the sun passes over the building. The other day, according to the lady down the hall's portable thermometer, it was 94 degrees at 10 a.m. Don't even get me started on the humidity...
posted by bitter-girl.com at 11:32 AM on July 24, 2011


I'M HOT BLOODED, THERE'S HUMIDITY
I GOT A DEW POINT OF ONE HUNDRED AND THREE
posted by tumid dahlia at 4:14 PM on July 24, 2011 [1 favorite]


So how did people manage before A/C?

Siesta, one of the most civilized customs in the world!

Temp 101 here at 6:00pm
Dew point of 38
Heat index of 97

No AC, but lots of shade trees.


Thank you FSM, for your noodley blessings!
posted by BlueHorse at 4:56 PM on July 24, 2011


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