Sometimes I think so. My cats will seem to eat more once the weather turns cooler in the fall but now that the summer weather is upon us (but not like Las Vegas of course) they might back off a bit.
Absolutely, yes. My cats have eaten 50% less food in the past 24 hours because it's 90 outside. It's hot and humid. I just make sure they have plenty of fresh water and attempt to make the environment more bearable for them...and me too.