Can excessive exposure to hot UV rays cause hair loss?

When midsummer comes soon with daytime temperatures approaching 40 degrees

What worries me is that I wonder if my scalp might be affected by such hot UV rays.

Of course, there are many times when I use a parasol, but

I also wear a hat.

But the center part is wide open, so

I'm thinking of buying another one that's blocked.

I saw somewhere that due to the influence of ultraviolet rays

I heard that it can cause gray hair...

I'm not sure if it's a fact.