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Someone put up a tent on their balcony to escape their heat-trapping apartment during the night.
(discuss.tchncs.de)
Third extended heat wave within 6 weeks.
The previous one exceeded 40°C, and the buildings not yet had time to completely cool down from that one before the third wave hit.
I was considering putting up a tent in my garden myself, but as I own a ground floor flat, the indoor temperatures did, with the help of some additional cooling measures, thankfully not exceeded 27°C.
I work in a foundry, and this is what I've experienced. During a heat wave the building is hot the first day, hotter the second day regardless of difference in temp, then hotter the next day. It then levels out pretty much, because the extreme heat is fighting to change not the air temp, but the building materials temp, in this case concrete and steel. It takes longer for the materials to heat than the air but once it starts going, the building materials continue to warm, because they also cool slower. Then even at night, it doesn't really cool off because it takes a long time for concrete and steel to release heat. Honestly the furnaces don't make much of a difference unless you're right up on them.