"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?
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.
Dew point is a much better measure of the oppressive, muggy, sweltering feeling than humidity. The dew point in Australia ranges in the 5ºc - 15ºc range at which 30ºc after sunset feels vastly different, way cooler than South East Asia where the dew point is constantly above 24ºc.
TIL. I see that in my country (Uruguay) the Dew point in summer is usually above 20ºc and some peaks above 26ºc (when temperature is above 30ºc with high humidity), no wonder it feels hot and oppressive (it's always humid, too).
There are plenty of humid, warm cities in the world. Not so many humid, cold cities. It's easy to check, usually the (English) wikipedia article of a city will have a Climate table with month-by-month data. On the winter months, Montevideo gets around 80% average humidity. I challenge you to look for cities that get as cold, but are more humid than Montevideo in the winter. You can find some (I think Auckland is one), but they are very rare.
Greetings from the Shoelace neighborhood, Montevideo
> The total heat transfer of a human is the same as the metabolic heat production, and is approximately 100 watts, or 400 kJ/hr, or 60-70 kcal/hr at rest.
It occurs by:
> You sweat a lot more due to the higher humidity.
It may be that you sweat the same at 30C (i.e., water coming out of your pores), it's just that with higher humidity the sweat cannot evaporate and collects on your skin in beads, which you notice.
Looking just at ambient air temperature is an easy mistake to make. I used to be like that, always surprised why people whine so much near the coast in winter with their comfortable numbers and thinking I’m superhuman compared to them. I stopped when I learned first-hand that their negative 17 degrees feel as bad as our negative 30.
If you live in a town in New South Wales where the average humidity is less than 50% in the wettest (or, should I say, least dry) season, you might not understand what it feels like in London where the average doesn’t dip below 65% any time of year.
Today London will feel at least 4 degrees Celsius hotter than Hong Kong. The latter is already an extremely unpleasant place to be in these conditions (and had in fact its own very hot weather warning issued), and unlike London it has a very strong culture of air conditioning.
4 degrees might seem like not a lot, but heat extremes are a tricky beast. Once your body cannot evaporate heat fast enough, you’re literally toast.
I'm in the northeastern US and it's very common for weather reporting to include the Heat Index (https://www.weather.gov/ama/heatindex) which takes temperature and humidity into account.
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.
As an Aussie who's spent time in Germany in one of these heat waves, this is definitely one aspect. But it's not just "keep the heat in". They are designed with huge thermal mass, so once warm they stay warm for a day or so.
When the heat wave struck, initially that thermal inertia works in your favour as the cool building keeps the interior cool. But after a day or two it heats up. Once that happens, the temperature at night doesn't drop. As you say, ventilation is not good, so the humidity rises too. The thing becomes an overnight sauna.
After one night of this, I went looking for a fan. In my Australian home, every room has a ceiling fan. In this German dwelling (rented by my daughter, an Aussie, for the past few years) there wasn't a single fan in the house, and worse none of the nearby shops sold fans. It looked to me like there was no "social knowledge" of fans or how to handle heat in general. I eventually got a fan off Amazon, who thankfully delivered the next day.
We were also there in another year in winter. These same buildings were amazing the cold. They could maintain a cosy inside temperature with very little extra energy. But geeze, you don't want to be in one in a heatwave that goes on for days.
Still doesn’t solve the cost factor. If you don’t have the money you don’t have the money. And if you barely have the money you’re probably going to take the risk because the risk is still very low.
It's not just cost. Many people in Germany claim they get sick or experience neck pain the instant they stand under an AC. I cannot relate at all and I'm very puzzled, but at the same time I don't want to deny their experience.
I'm Lithuanian and that's my pet peeve when making fun of my culture. I think it comes from homeopathy BS that has roots in Germany.
Funny enough Germans appreciate good ventilation, but here we have following: wind outside - ok, same wind inside (draft) - you killing me. Always wear slippers inside, protect your feet and neck from coldness. Avoid AC at all costs, especially bad if it blows right into your face. Also no fans right into your face or body. Wet hair - do not under any circumstances go outside. Even the most respected people I know fall into this trap.
Possibly some confusion comes from rhinorrhea - people mix up these symptoms with actual disease. And most ironically lack of appropriate ventilation increases spread of respiratory infections.
Last decade+ we had a bit of a HRV fad, wonder if that is reflected in some stats. Anecdotally I heard people shut these off to save power and open window instead...
That doesn't matter for portable AC. Most people build a plexiglass or foamboard plug for the open window. Some products are sold already set up like this. If you can fit a casement AC that also probably doesn't matter. You can probably remove the window too I'm guessing.
Portable AC exists and people do use it, but it's loud and awkward with casement windows. This is a bandaid solution at best. Yet, I've seen them sold out in the summer, so people do use them.
You'll probably want a split unit. Minimum $600 including install in Eastern Europe, but more likely to be over 1k.
Extrapolate salaries, cost of living and that's more like 3k in your money.
That said magic happens when government subsidizes things. Friend spent 8k euro for 10kW solar + 15kWH battery system, of which government reimbursed 7.8k. 1.35k USD for entire system, when you'd pay this much for someone to plug some cables for half a day.
If they are insulated properly (lots of roof insulation) it also keeps the heat out. I'm building a house and last week it reached 32c here, inside got no warmer than 23c on the upper floor. I don't have AC installed yet, just HRV.
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.
It’s not different if you’re used to. Heat acclimation is a real thing, but it won’t magically beat physics if wet bulb temperature hits body temperature.
No worries as they'd had their vegemite for brekkie providing all the salt they need to offset the constant sweat. None of this soft modern electrolyte bullshit, just beer dregs on toast.
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.
I tolerate heat well, I feel very comfortable at 28C but I get cold easily. My sister is happy at 18C and starts overheating at 25C. Not everyone is the same.
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
My understanding is that full heat acclimatization requires elevated core body temperature for 30-60 minutes a day for several weeks to really kick in and it’s easily lost during winter. Someone going largely from air conditioned to air conditioned building during the summer months may not even build up much of a passive acclimatization.
I don’t do as well in heat so for the summer hiking months in California so I have to do a two week sauna or hot bath protocol, otherwise I struggle really badly during the season. YMMV of course.
Same. There definitely seem to be strong genetic factors (just based on my personal experience TBF). I also notice I adapt substantially after two to three weeks of consistent exposure. But it does have to be consistent - hiding out with AC 24/7 prevents it.
That’s because you pay attention to your body and you’re not in denial. Above 37 degrees, your body cannot regulate itself, and it starts being seriously uncomfortable before that. Going outside for a run when it’s 40 is unbelievably stupid.
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).
Yeah we ve reached stupid levels of weather scare. France did have some extreme temperatures over 42, but 40 is a typical Mediterranean heat wave, not Armageddon
It’s litterally the hottest month of June ever registered in France, beating a 23 years old record. Very typical heat wave indeed.
EDIT: actually yesterday was the hottest single day ever in recorded french history, and it happened in the merry month of June, not August. Truly your typical heat wave.
EDIT2: I was wrong, the record is not actually 23 years old, but… 1 year old, as the record had already been broken in 2025. Can’t wait to get my next dose of very typical 44C temps in may next year.
I imagine the buildings there just aren't built to support that heat plus the body height of hundreds or thousands of attendees?