Hello Jennifer Beilke,
The simple math says, no…calories are expended per length of activity.
You may get a false sense of burning more calories in the heat because some people tend to lose their appetite and stay active more hours during the longer, warmer days.
Also, you may be getting dehydrated, which is something you do not want to let happen. The high humidity makes it very difficult to hydrate properly with the body fighting to stay cooler.
Please be careful.