There has been mention that British islands could see 104F days!!! I've got some tips. Feel free to add more.
Being outside and indoor suggestions at 104F: First NAKED, but watch the hot rocks, asphalt and concrete under bare feet.
--shade makes a world of difference, especially with breeze.
--periodic outside shower, or garden hose, but watch that the sun doesn't heat up the water left in the hose to scalding.
--a simple fan. sometimes you can rig a cooler pad to drip and create an evaporative cooler outdoors, or in.
-- sauna may be hot, but 104F feels refreshing after that. You will get the effect of exercise that you won't feel like doing, from sitting in the sauna, too.
--Cool drinks, hydrate excessively, pee clear often.
--swimming pool, bathtub with cool water, bags of ice when it gets warmer, ice cold plunge for 90 seconds will keep you cool for a while AND like the sauna, your body will react like the effects of exercise.
--TRYing to sleep at night: get a tent with a bug net if you have to, but sleeping outdoors is fun. Here, in the olden times before air conditioning, people, rich people, would sleep in the upstairs where the breeze would run down the hallway opened on each end, with a bug screen. Also a roof, if you've got one, but remember that it is hot on a roof, until the night cools it off and be careful if you rollover!
--Stealing your grandkids kiddy pool and adding a bag of ice that you got at the liquor store when you bought your margarita mix is worth the flack.
--Cool drinks are great, but not too quick and alcohol will dehydrate so drink more liquids with your BEER.
--Beware the phone. People will call you up just to bitch about the weather.
--A person can actually drive a car with just two fingers when you run out of BEER), but not you, because you can get a stronger buzz when in the heat. Oven mitts are slippery to drive with. Try work gloves.
--Best to put a shade under the front window of the car.
-- and about that drinking thing. I was in a speedboat out on a lake for a few hours in Missouri (yup, naked story) drinking BEER. Ozark 100F with 90% something humidity. I'd got off that boat at the pier and was stumbling wasted by the time I got off of the pier onto land. The heat can fool ya, and whoosh you're suddenly wasted. Think cool house out into outdoor 104F.
--A spray bottle with water in it. Forget the cats, turn it on your naked self.
--Hang out in any place with airconditioning, if your old place doesn't have it, OR if it does. The cost at the end of the month will be stunning to run one. Instead invest that money into a goof time at a pub, or something (probably similar cost). Libraries, specialty food stores (again similar costs). Movie theaters, but not all day.
--say something threatening about your government and wait for them to come get you for waterboarding, so you can end the torture of the heat!
--Don't park in front of the store. Park in the shade, but beware of others with the same idea. In the circumstances, they could be "murderously" competitive.
--visit natural water source, lake river. Get in, take off suit, and enjoy skinnydip. No worries you probably won't have to put it back on. You will stay in the water.
--fuggit, get a ticket to a place with very high mountains. Go there, immediately.
--If it don't break your body down, that kind of heat will break your bank account...or, have your nudist friends chip in and have a party with an entrance fee...like $100! Community! Rotate hosting at homes.
--Your car has an air conditioner, most likely. If your house doesn't.
--Imagine a cop coming up to you in kelvar armor, long sleeves, helmet, long pants and jackboots and arresting you for indecent exposure, or telling you to get dressed!?!
--You can also use your car to bump into a fire-hydrant letting all of that cool water loose and spraying every which way. Umm, yummm....
--Beware of the neighbor who hooks a hose to your house and tries to flood his own basement to hide it.
--No sheets, no blankets, no PJ's.
--A naked walk on a warm evening, especially with a full moon is divine.
--watch diligently about cigarette butts being dead out.
--Sit inside in front of the cooler and make lists of things to do to cope with the dang heat!
--take the time while stagnating indoors to look into the causes of climate change.
--Did i mention stay completely naked, your best defense!
--Baking in the oven will do amazing things to screw up precious cool air in a kitchen.
--clean out that mess in the basement that you have been procrastinating about FOR YEARS. It's cooler down there.
--Water your plants at the roots only. The water spray will magnify, heat up and burn your plants.
--shade netting, cardboard, any shade will save plant's agony
--Black, or dark cars, searingly hot
--a tail pipe exhaust from a passing car can ignite dry grass in a moment. Only you can prevent wild fires.
--chrome handles burn blisters, in moments!
--Crack the windows of your car just a bit, just let the heat escape. If you don't, climb in for a few minutes of 140F heat and then it won't seem so hot when you crawl back out.
--Jbee...true stories, nearly all! First hand experience. Guaranteed results....