It's not that long ago that I'd welcome a cool 27C day, as it crept up into the 30s here.
(Worth noting that, if the C were replaced with an F, those temperatures would be quite common where I'm from in the colder part of the year.)
Sure but you're forgetting the high humidity part. Years ago I visited family in Phoenix and temperature there was over 100F but it's a very dry heat and so there is very little sweat. The heat we have in Denmark feels worse because it feels more like a rainforest than a desert. Up near Lake Havasu I experienced 119F and it was damn hot but still didn't feel as bad as 30C/86F here in Denmark (both felt bad though).
Also we don't use AC here in Denmark so there is that.
We've been having high humidity here as well. Those 80-90 degree (F of course) days were also humid, and it did become uncomfortable without air conditioning. (Fortunately, the house is air conditioned.)
Then again, sometimes the air conditioning doesn't work as well as it should. When it's humid but not particularly hot, the AC does not go on even though having it on would make things considerably more comfortable. There was also that one time when the temperature got down close to -40 degrees (F or C, it's the same temperature), but the AC went on anyway (I had to set it to not go on at all until it started to get warm again); at that temperature, it is clearly heat, not AC, that's needed. (I did *not* go out that -40 degree day; the rest of the week, while not *as* cold, was still frigid, but fortunately fleece leggings really help in that sort of weather, so I wore them when I went out.)