I've been sober about a month and a half. I'm much less bothered by the heat and humidity now than I have been in summers past when I was drinking. When it gets into the 80's or 90's and is humid I sweat an appropriate amount and don't feel woozy.
Not sure where you're at in your sobriety but I'd venture a guess that a couple of weeks sans drinking should improve heat/humidity tolerance quite a bit.
Stay cool, you!