Well, its supposed to be 97 tomorrow, 98 the next day. I wanted to prime some Tiger Schurzen I redid for a project that refuses to be completed.. If I recall, high temps like this are a no no.
Some have suggested skipping priming altogether, as it diminishes detail. Not sure if that is wise with brass parts though.
All foolishness aside, I am assuming you prime outdoors ... as I do. My wife has no problem with my airbrushing Tamiya, Vallejo and Lifecolor, but the Gunze stuff is a big no-no. So, when I prime, I am relegated to the back deck, can in hand. Even on really hot days I can't recall ever having coverage or adhesion problems on anything I paint outside, and I prime everything. Of course, I don't let anything heat up under the sun either. But I've done this for a few years now and have not experienced any ill-effects. I rattle the can, hold the part, step outside (moving a distance away from the house deemed acceptable to the wifey) and spray away.