Peoples struggling with hot buildings overnight, evaporation takes energy and will cool your building, even a light spray of water on your exterior (especially concrete/paving patios) will help cool you down overnight #BuildingScience
Update on keeping cool. If you have water shortages, do the evaporation trick on your body. Wet a cloth, wring it out and put it around you. I have a sarong that I used wrap around me in the desert. Everyday was about 45 deg C. As @skribe pointed out, this does not work as well in humid places.

@SeaFury @skribe

This is the stuff of my recurring nightmares. Sometime in my lifetime, somewhere well populated will reach wet bulb 35c. This means that evaporation temp you are getting to is so high it doesn't cool us down. A healthy adult male is projected to survive 6 hours in that.

My recurring dream is that I'm somewhere in the mid east and walk out of a hotel room to see street after street of bodies of people who didn't survive the night.

@chu @SeaFury we already get days of that here. 15 or so years ago, you might get a day or two reach 31-32C but most days would be 30C. Now, even the 'cool' days are 33C.
@skribe @chu if electricity goes out… you might have to rely on special phase change material vests … because sweating will not fix you if the wet bulb temp goes above human survival temp.
@SeaFury @skribe One of the things I appreciate about Melbourne weather is that when it is hot, it is not humid. Whereas Brisbane might not have gotten quite as hot, but you could never ever cool down by, say, walking into a shower fully clothed. (Yes, I have done this in Melbourne on days when it was over 40, before I got my aircon.)

@SeaFury I've had people look at me weird when I suggest spraying hard surfaces in this manner

seems like a pretty effective thing you can do to cool things!

@SeaFury This is so common in Tajikistan it's practically a ritual; people hosing down their concrete all the time. Nowadays I'm seeing it less and less in the capital.
@ben These low tech, practical and lowish cost things need to be bought back!
@SeaFury not in high humidity it won't 🤣
@skribe OK, Less effective in singers. Plant more plants around your walls!
@SeaFury Firstly, I live in an apartment (HBD). Lastly, there's greenery all around where we live.

@SeaFury
That is not really a concern in Lutruwita (yet), is it?

The heat, I mean, not thermophysics.

@PetraPanda No, we are quite temperate here. A few days we get to 40 and people start complaining LOL, but we survive ok. Our houses are well insulated.
@SeaFury I have used wet cloth on the forehead for better sleep in a hot sleeping room. I got the idea after noticing the effectivity of spraying my head with water while cycling in hot weather. A spray bottle proved the best way to dose water, because I only needed a bit of water to great effect. While sleeping, you don’t want to spray every 15minutes, you want to sleep! That’s why the wet cloth.

@SeaFury

Problem, there already is a water shortish!

@Luuk_Aalders :( Of course, if you have a water shortage then you don't do this!
@SeaFury
But the best ac is the nature
@SeaFury Excuse me but shouldn't that water be reserved for the needs of data centers?? Yrs, Sammy Altman, dipshit.

@SeaFury to add to this, we have a sprinkler on our roof, attached to a tap timer, set up for 10 seconds every 10 minutes or so, long enough to make the roof moist, short enough so it doesn't just run straight down the drain. You're aiming for the roof to evaporate the water. On really hot days I manually hose down the Sun facing wall every hour or so. Also close all the curtains, close all the doors to rooms that have an outside wall and drink lots of water.

Source: I live in Perth Australia

@SeaFury shall I do each evening or early morning asking for a friend
@mamapanda Prob better before bed so you can have a cooler house to sleep better.
@SeaFury when we lived in Erskineville there were impromptu late night meetups on hot summer nights. People would wander out into the street and hose down their house exterior with the focus on the tin roof. Those old terrace houses used to get (and stay) hot and needed some help cooling down.
@SeaFury and if your building is of porous materials even better as it will act as natural air-conditioning as temperatures rise and the dampness evaporates from the walls