In Canada - and it does get cold here, and hot here. You can't work outside every single day, but you also do not have to stay at home or indoors every single day. I lean toward being outdoors for as much as possible of the year. There's no perfection about it.

There is a lot of research that spending time in nature, even if the nature is not ideal (bare trees, winter, bad weather, too hot), has measurable impacts on human cognition, memory, and similar mental benefits. It's not even correlated with mood improvements: even if you return indoors more miserable than you left due to the weather, you still measurably mentally benefit from spending time in nature.

Find some shade and don't stress it Europal! (I hate climate change too.)

Not the person you're replying to, but this is genuinely the killer feature of the UK. Yes, we get heat waves and more of them now, but it's much better than mainland Europe. Especially if you stay away from London (which I would recommend).

You live somewhere where you can't go outside "most of the year"? Did we evolve on the same planet?