I spent most of my young adult years in the South. I went to basic training in Texas, in July. I have lived along the Gulf and know the meaning of hot and humid.
But what I've come to learn is your body adjusts to where you're living. The first year I lived in Colorado, I wore my heavy coat any time it was under 70 (part of that was being cold, and the other part was that they didn't issue officers coats, so I was going to get every dollar's worth of use out of it). By the time I left Colorado, it wasn't unusual for me to carry the coat to the car and leave it there, even in below freezing weather (I layered of course, but still, no coat).
When I first contemplated moving to NYC, I couldn't imagine it being hot. But it does get hot. The heat has no where to go- all the buildings get in the way it seems, and reflect back heat as well. The other day E told me some yahoos were complaining (complaining!) that we'd not had a day over 90 yet this summer. I blame today's heat on them. Once you add in the city heat factor and the humidity, it's darn uncomfortable out there. And don't get me started on the ovens called subway stations. The subway trains are air conditioned (sometimes too much so), but the platforms are not. I'd rather walk...except that you know, it's HOT. Luckily I take the bus, and that's a little better than both options.
Logically I know I've lived in hotter places. I can't imagine how hard it would be to be pregnant and living with triple digit temps that were normal for some of my old haunts. Thankfully I'm not super big and so only a little uncomfortable. I feel for the women who are in third trimester!