Definitely kills my appetite whether or not I’m in air conditioning. I tend to eat a lot of cereal and cold cuts instead of anything that needs to be cooked.
For some reason I get wicked cravings for salty stuff, too, although I work in an air-conditioned building and try not to move around much otherwise so it’s not like I’m sweating too much.
Yep, I think there’s crack in them. I also discovered Magnum double chocolate ice cream bars.
I lose my appetite in warm/hot weather, but then my appetite’s a bit wonky anyway (hello, no-thyroid issues!) Like someone upthread said, though, I get a huge salt craving at this time. Potato chips? I’m right there 
This is the only time of the year where I’ll go near them.
I feel compelled to make stuff, though, just on the remote chance we might starve to death. There are only so many frozen yogurt/deli turkey/pasta salad meals you can eat…
I find salads are much more commonly found in my diet when the weather is hot.
Today two of my meals consisted only of ice cream and water (it was 97 degrees out most of the day).
Today was fairly hot and humid. I couldn’t be bothered to eat a real lunch and had a salad for dinner.
More than “killing my appetite”, it changes it. Chick pea soup? Ugh, no. Roast? Only if it’s as a cold cut. Salads? Yes, please. Gazpacho? Oh yes. Try to feed me gazpacho when it’s snowing outside and I’ll be checking you for fever.
Appetite for what? 
As with others, I wouldn’t say it kills my appetite, but it definitely changes it. I crave fruits & salads, ice cream, fluids. Still like some hot foods like burgers, steaks, etc, but prefer cold stuff!