I actually experienced this during Saturday's very hot Civil War Century in a major way:
From that link:
Did you know? The opposite response happens during exercise in hot weather. Instead of feeling like you can scarf down a Thanksgiving turkey, you’ll probably have little or no appetite at all. That’s because the body is doing everything it can to cool down and eating food, thus generating heat, is not on the immediate agenda. However, it’s times like this that you must eat to quickly restore your glycogen, a.k.a. fuel stores, in order to keep your energy levels up and recover.
By the 3rd rest stop, I was sucking salt off peanuts, rather than eating them. The 4th rest stop is "famous" for it's tomato sandwiches. I couldn't even look at them (might have been the mayo, too, oozing out of them. Blech).
I read somewhere (wish I could remember where) that you don't actually burn more calories during a cold workout vs. a hot workout, and that people use their feelings of hunger after a cold workout to overeat (alluded to with the swimmers in the link).
2007 Seven ID8 - Bontrager InForm
2003 Klein Palomino - Terry Firefly (?)
2010 Seven Cafe Racer - Bontrager InForm
2008 Cervelo P2C - Adamo Prologue Saddle