Originally Posted by LapLap

Between late October and early May? Sure. Yes.

During the first two weeks of July?

I coped way better with Japan’s summer heat in 2023 than I expected to. So much so that I was back for another month in 2024.

I thought about going to Fuji-Q with my daughter and staying there overnight. Ended up cancelling our reservation as I realised what being there actually meant (it is more exposed than the Disney Parks.)
We didn’t end up climbing Mount Misen either, just wasn’t high enough to be cool. We did spend a night on the island and had a lovely time, if we’d have had a second morning there I would have gone up.
Our plan was to spend some time in Hiroshima, alas the rain during those hours was epic so we went earlier than scheduled to Kanazawa. Turns out there is loads to do in Kanazawa at 6am.
If Himeji castle isn’t air conditioned getting to the top will be an ordeal during opening times.

In summary, my advice for getting the most out of a July visit is to choose activities you can do very, very early in the morning. Unfortunately, this approach invalidates the concept of day trips since you will get the most out of locations you can wake up in or near to.

Go up Mount Misen? Sure, just start climbing by 6am (be sure to have lots of mozzie repellent)
Imperial Palace, Tokyo? Pass. Opens too late.
Nagashima Spa Land? Why not?

My dos céntimos as a heat tolerant Spaniard.