WHere I live its really hot, 110+ during the sumer months. Today was a lot cooler 95 but the humidity level was 45 percent. THe training felt like a sauna suite workout. Now I know how people feel like in Florida. Hard to get a good workout when you are so drained from the heat.
It doesn't get that hot over here, but humidity gets pretty high, so 85 degrees feels pretty hot. When it's that warm I take it easy during boxing workout, short warming up (duh), two or three rounds of bag work, and some sparring. I make up for it by running or cycling late at night when the temperature drops.