[shitloadofbooks]

"Extreme Heat" seems to be 37-40 degrees Celsius which is bafflingly mundane to me as an Australian who grew up in rural New South Wales. We'd pack 30 kids and a teacher into an un-airconditioned classroom with just a ceiling fan and the windows open in that temperature.

I imagine the buildings there just aren't built to support that heat plus the body height of hundreds or thousands of attendees?

[jcranmer]

People tend to rely on air temperatures when in reality the lethality of heat is probably more linked to the wet-bulb temperature.

The human body has a natural resting temperature of about 37°C, and metabolism of course generates more heat constantly, so we constantly have to shed that heat. When the temperature is low, we can rely purely on conducting the heat into the atmosphere to shed the heat (which is probably why internal body temperature is higher than the atmosphere!). At higher temperatures, conduction is less efficient, or sometimes even adds heat load into the system (at above 37°C, obviously), so we start relying on evaporative cooling (i.e., sweat) to cool us down.

The wet-bulb temperature is the minimum temperature that can be reached by evaporative cooling. So when the wet-bulb temperature is in the mid-30s °C… people start to become literally unable to regulate their core body temperature, and the heat is lethal. Wet-bulb is largely a combination of the temperature and humidity, but unfortunately, it's not typically reported in most weather reports, so people go off of the air temperature (and the humidity) that is reported.

Which is a long-winded way of saying "the humidity matters a lot for how much a given temperature is bearable." I don't know what environment you come from purely by rural New South Wales, but my first guess is the semi-arid and thus low-humidity bush regions of the state, which means the apparent wet-bulb temperature of 37-40°C would be a lot lower than the equivalent 37-40°C for most of the humid continental climates of Europe.

[maxerickson]

Humidity makes a big difference in how stressful the temperature is (wet bulb temperature accounts for this somewhat). The age of the attendees and the tendency of the building to heat would also be factors.

[germandiago]

Spanish here. Same here.

I think they have been spreading the paranoia for years as if something abnormal was happening... I am not sure, that first thing. Second: even if the weather keeps shifting (I would say more slightly than what they tell us or continuously "suggest" with headlines in the media), these temperatures are bearable by humans with a few cautions depending on the age group.

I used to go jogging midday in summer in Spain, near Valencia, in the seaside. Almost 40 degrees (sometimes I guess 40 or more).

It is hot, true, but if you can resist this kind of impact and you do not expose yourself to the sun in stupid ways (like many hours in a row) nothing bad is going to happen to you.

The headlines are all the time alarming people and sensationalist, even if the cancellation is there.

[cjonas]

I've always assumed there is some sort of "acclimation" period, maybe even related to the conditions you grew up in. I much would rather spend a time outside in -40c (with proper outerwear) than 40c. I'm relatively healthy but I feel like my body shuts down at anything above 36c

[human305893]

Euro buildings are built to keep heat in. Aus buildings are leaky tents.

[eisa01]

That should actually help you also with AC: Keep the cold in, and reduce the electricity costs

[lazide]

For some reason they seem allergic to AC - see the rest of this thread.

[nomilk]

And that was after running around a semi-arid playground playing 'tips' or touch footy during recess and lunch!

[weightedreply]

We need a humidity comparison to go with temperature.

I grew up in a humid city and summers were unbearable. Now I live in a dry climate and 30°C is pretty comfortable.

[tzs]

How does the humidity in rural New South Wales compare to London?

[gonzo41]

Depends, In northern NSW, the heat it humid, in the south / west it's usually dry. It gets hot, like opening a oven door, but it's not a wet humid heat that kills you.

[anthk]

40C in the Atlantic Spain with the Foehn effect (weather for today and tomorrow) would make 30C in Australia a joke.

The humidity here it's hell. You feel 35C like ~42C in dry climates.

[eloisius]

A lot of it is acclimatization. In Taipei this morning, at 9:30 it’s already 31C and 73% humidity, forecasted to hit 37C by noon. My first year living here this was unbearable, but now it’s tolerable. It’s just summer, not a spurious heat wave.

[winstonp]

the British are notoriously sensitive to heat. They'll call 30 Celsius weather a heat wave.

[zoenolan]

https://youtu.be/mMqkuAb-HYg

[jorl17]

I'm from Portugal and I start losing it at 25. 30 degrees is insane.

Last summer my house got to 39, and I didn't have AC (it was broken). I think I'm still recovering.

[ornornor]

I had 40 Celsius today at around 9pm. Middle of the night now and it’s 34. It’s as cool as it’s going to get before it starts heating up again tomorrow. Where I live there are no laws on max temperature in residential housing so the owner (I’m renting) doesn’t have to do anything about it. Never mind the poorly insulated, black slate roof (I’m on the last floor) or lack of AC (I’d have to foot the bill anyway).

[wil421]

That’s normal where I live in the Southeast US from late May to late September. Plus 60-99% humidity, I can see the air in the mornings.

There’s something about 85F/30C and 80%+ humidity that prevents the temp from going much higher for a longer period of time.

[bavell]

Yep, 9:30p here and it's 82F/80% humidity. Still pretty mild compared to the deep summer months (Jul/Aug)!