Oh, that's so right - if the summer temperatures get up into the high 90's or over 100 for a long stretch, your tomatoes will just stop flowering. They also do that here when the night temperatures get above about 75.
My kids live in Salt Lake City, and some summers their tomatoes stop flowering for about a month over the middle of the summer if they get a sustained run of 100's. Some years they don't, though.
I've had luck both in Salt Lake and here in Florida with the smaller fruited types of tomatoes - cherries and grape tomatoes seem to bear in higher temperatures. They can go well into June for me here which is nearly a month longer than regular tomatoes.
