According to The Vane;
If you are in Europe, particularly northern Europe and don’t have air conditioning, and aren’t used to dealing with this kind of heat (humid), I’ve got a couple of tips. Humidity sucks because it doesn’t allow for the cooling evaporation of perspiration.
I’m in Toronto, and we regularly get stretches of over 30 degrees celcius, and it’s generally very humid, which is different than dry heat. I also do not have air conditioning. Now, I’m very lucky in that my house is surrounded by trees, which also allow the raccoons to get on the roof and crap all over the place, but that’s another issue. The trees cool and shade the house significantly.
So; at the very least, close your windows during the day and close the curtains; you want to prevent the hot moist air from coming in, and to block sunlight from heating up the house. When the sun goes down, open all the windows and hope for a cross-breeze, and if you have multiple storeys you should get stack effect cooling as the cooler air enters through the lower windows, and the hot air rises and escapes out the upper floor windows. I can cool my house by a few degrees overnight by doing this.
If you have fans, stick them in front of the windows to pull in cooler air. Even better, if you can position incoming fans where the prevailing wind is coming from, and fans to vent the hot air at the opposite end of the house.
You can also make “swamp” coolers by putting ice cubes in bowls and having fans blowing the cooler air around. This is a fairly localized cooling method. Apply cool, damp cloths to pulse points, and the back of the neck.
Sponge bath in tepid not cool, water to cool off when necessary, dry in front of a fan, talcum powder is your friend. Do this before going to bed and sleep with a fan directed at you. Dry, light, loose, cotton or linen clothes.
Stay out of the sun, especially during the hottest parts of the day. If you’re outside, seek shady, breezy spots. Seems obvious.
Check elderly family, friends and neighbours; they are the most vulnerable. There was a horrific loss of life in France a few years ago as elderly people died alone from heat stroke.
Pets also; they will need shade and water.
Hydrate, hydrate, hydrate.
Here’s a link to WebMD to recognize and treat heat stroke;
And finally (unless I think of something else), check the comments to see if others have some good suggestions.