Remember during Gulf War I (the retrocon name given later) at work with us all watching TV to see the live war coverage. Helps to be in the same time zone as Bhagdad, and CNN popped over to the London correspondent about the current UK heatwave, with temperatures hitting the highest of 31C. Asked my colleague when was it 31C by us, and he replied it passed that at 07H15, and was, when he went through to tea, just a shade under 45C indoors. AC unit for our section having kind of moved large chunks of compressor off the roof a few months before when the compressor decided that throwing a rod was only the final thing, and threw heads off along with the rods.
Peak we measures was 75C 1m under the concrete roof, and we went through 100l of water a day, between the 12 of us in there. People looked at me funny when i remarked a few times how cool it was outside, only 41C, till they came in at lunch time. Most popular room was the ATE system, with it's separate AC system, made from 3 Defy 36000BTU console units, and those would be repaired post haste, as otherwise there would be no flyable aircraft.
Plenty of people came for winter holidays, and dropped dead from heatstroke, even before noon, while us that had been through a summer or two were out wearing jerseys, because 25C was cold to us.