Daily sauna use. You have to get HOT to feel cool. You will become heat adapted, feel cooler, and sweat less. Plus it has great cardiovascular benefits.

Air conditioning

It’s been so hot where I live this week that 30c sounds nice. It was 36c during the day yesterday but felt like well over 40c. It felt like an oven. It’s 27c right now at 1:30 am. So here’s some tips- Drink a lot of water. Stick to the shade. Keep a wet towel around your neck. I wet a baseball cap and wear it. Don’t be in direct sunlight light for long. If you don’t have a/c, I know most don’t in UK, open two windows on the opposite side of the house to create a drafted. Hang and secure a wet towel over the window where the wind enters and it will act like a natural a/c. Won’t do a ton but it will lower the temps inside a few degrees. That’s all I got.

If you live straight under the roof and it’s hotter inside than out: close the blinds, open the windows.

Otherwise, keep everything shut, close the curtains, get some stick on sun shades for your windows. Open everything at night, then keep an eye on the heat in the morning and shut everything when it gets hotter outside than inside.

Have lukewarm (NOT COLD) showers. If you have a bath, fill it so you can cool down every now and then. Also fill a washing up bowl to put your feet in.

Get a fan. If it’s not too humid, hang a wet towel in front of it or pile some of those bricks you use to cool a cooler in front of it.

Wear linen, viscose or modal. Don’t wear trainers.

Ice packs, fans, portable ac units, misting yourself. It’s not so bad after you’re 35+

I live in the US, and the forecasted high for today is 39°C 🫠

I read your post earlier today and I am right at the ocean but can’t go into the ocean water to cool off because it’s currently a biohazard right now smelling like sewage apparently so I walked to the beach shower and cooled off at the beach shower.

Don’t be overweight, don’t drink alcohol, stay indoors, have a portable fan with you always, drink lots of water

I made a post about my most effective tip. Works pretty well.

Evaporative cooling.
Cool, damp cloths, especially to place around your neck or on your face and wrists. Cool showers. Avoid any use of the oven and minimize use of the stovetop or any other device which produces a significant amount of heat. Keep blinds/curtains drawn while the sun is out. Open these and the windows at night. If there is any breeze and your home’s layout is amenable, open windows to promote cross-flow. And, if safe, doors. Lightweight, breathable clothing. Avoid going out during the hottest part of the day unless it’s to somewhere air conditioned. If you drive, try to park in the shade and cover your windows when parked to reflect sunlight. If public transit, heavier on the avoiding going out during the hottest part of the day. Hydrate. This means electrolytes, not just water. Cotton sheets can feel cooler than not using any bedding at all.

Not much real relief without A/C. Go somewhere with A/C until the sun goes down.

Solo wet T-shirt contest.

Soak a wet rag and drape it over your neck. The evaporating water will help keep your neck and shoulders cool, and you can wipe down anywhere that needs a little extra evaporation.

Loose, light clothing. You want air close to your body to be able to move, but also serve as insulation to an extent.

Down here in the US south, the old school default was cotton seersucker. It really is better than other types of fabric, but it’s harder to find nowadays. But any clothing that’s got a bit of room to breathe is going to be better than something close fitting.

Any of the methods of cooling an area are going to be improved if you dress for heat in the first place

Put up exterior shades on the south side of your home or at least outside your windows. It keeps the direct heat from the sun from baking your walls and windows, and you on the other side. Yeah boy, window awnings and sun shades are in.