Simply this depends on the clothing and environment you are actually in; here in Florida the workmen all wear full covering gear like hoodies and sweatshirts simply to avoid the harsh Sun. In fact some days of combined Summer plus heat plus humidity it is an effort reaching the letter box ;)
But who would suggest I am unfit :)
Generally eight glasses of 8 ounces of water per day, half that is you are doing nothing except hibernating in the snow; you get the idea. Hot humid workers like workmen will need to double it, depending even triple that amount, now you are getting close to heat cramps and heat exhaustion where you can no longer think correctly...
Teenagers and young adults even just visiting the gym might need 64 ounces or more to hydrate and detox their body's...
So do your cells a favour and grab three cups of water now !!!
When I became ill with diabetes I always wanted to drink. In fact, the thirst is one of the symptoms of many diseases!
I drink beer.