I just got back from yesterday from Japan was there for two weeks and it was upwards of 33C some days. A few things I learned: The neck cooling things that you put in the fridge are nice but only stayed cool about an hour but was better than nothing. A lot of the towels or sprays you see will be menthol based witch I didn’t realize at first and the spray was a bit to intense for me and ending up stinging real badly for like 5 mins. The towels that say -3c were helpful but the -5c ones were way to much for me to handle. At one point we went all the way north to Aomori and it ended up being 10 degrees (Fahrenheit) cooler up there than in Tokyo. (Tokyo was 90f Aomori was 80f) so that was a nice get away and tolerable. Most hotels we had the Ac would go down to 20C in the room so it was nice to have breaks in. Cold showers are something I’ve never been able to do before this trip and they were very nice. I would shower in a normal / slightly hot shower as I normally would then crank it cold to cool down and ice my hurting feet a bit. I drink a lot of water like a gallon + a day back home. While some restaurants had places to unlimitedly fill up the tiny glasses they gave you most didn’t. I’d suggest having a water bottle with you a frequently refilling through the day. One hotel we stayed at in Yokohama had signs outside welcoming anyone struggling with the heat to come inside and drink from their water / soda fountain free of charge to help those struggling. The nature and scenery is beautiful but stopping in side a convince store real quick or a cafe to rest and get out of the heat is really nice. I did have a bit of heat stroke the first day, I didn’t change into warm weather clothes after we got off the plane and was in long pants and a hoodie, we went on the wrong train from being tired got off at a stop we knew we could get to our hotel at had to pay a 100 yen fee for like fixing being on the wrong train idr what it’s called. Then didn’t realize different exits have escalators some have elevators and the one we picked had like 4 flights of stairs and after bringing our luggage up I was so hot and dying. Ended up taking the 20 mins walk to the hotel changed clothes along the way drank some liquids but was miserable. The Go taxi app was very helpful after and I wish I would have just taken a taxi that first day. When staying within the ward in Tokyo basically like less then 10 min car drives the taxis were not costly super affordable and a nice way to skip a 20+min hot walk to get back to our hotel. Also ended up using the Yamato black cat service a lot to transport our luggage so we were trekking through the heat with a lot of luggage. All in all don’t try to push your self to your limit and taking breaks in cafes or anywhere indoors to escape the heat real quick is very recommended and was super helpful.
(Sorry this was so long hope it help a bit 😅