I think false pics depend more on humidity than actual temps out side. It has been around 100 degrees here a cuple of times for 1 week at a time and I still get no false pics. I make sure my camera is in the shade for the hotest part of the day and that the sun will never directly hit it.
It was over ninety for at least four days out of the last week. I've got one setup that the week before had only four pics, this week in the heat had fifteen. I'm with davered, I think the way you set it up has more to do with it than how hot it gets. Most of the 4 to 5 false picks I get per roll are night time any way, and I think thats because I don't run a refresh on my PF... I don't get false daytime shots because I set up in the shade. At least thats what I tell myself, LOL
It's been in the 90's here in WV and still hot and humid at night. Now it's going to be around 85 during the day and 60 at night so i put mine back out today. It's in the shade and by a watering hole. No bait this time but im hopeing this will cut down on the coon and fox pics.I'll go check it on Wed. and see what we got. Mike