I've been surprised this year at the continuous amount of tomatoes I have gotten all summer. I have had hot summers before where I have literally gotten no tomatoes after June 1st until it cools down for fall because many tomatoes stop setting fruit when it stays above around 80 at night. This summer certainly qualifies. So what gives? I think this year I did a better job of selecting heat tolerant varieties which will fruit in this weather. Cherry tomatoes are always reliable for this. Juliets do a very good job. Some others I planted this year include Cherokee purple, Azoychka, and Arkansas Traveler.
That said, the heat has taken it's toll the last month or so. In fact, many of my tomato plants I have gone ahead and chopped back a half to ready them to go in fall. The rest will be done by the first week of August. I did this last year and I got a fantastic crop in the fall. I had tomatoes going all the way until frost last year.
So do your tomatoes a favor. If they are still healthy, cut them back by half so they can be ready to perform when the weather gives us a break.