Most of my friends who live in FL do two crops a year and I first heard about this many years ago from Linda Sapp who owns Tomato Growers Supply Co in Fort Myers, FL. It also obtains for those who live in zones maybe 8b to 10. BTW TGS is ab excellent place to get OP's and hybrids both and she knows Drl Scott ( see below) very well.
Seeds for the Spring crop are sowed between Xmas and the first part of January and plants set out in late Feb to early March so that fruit set and ripening occurs before the high heat sets in.
The Spring crop should be mid season and late season varieties.
Seeds for the Fall crop are sowed around mid-August or so and plants set out late September. These should be early and midseason varieties.
It isn't just the high heat that causes blossom drop but also clumped pollen from sustained high humidity, which is much less effective, so it's kind of a double whammy, if you will.
Some let their Spring crop plants get thru the summer by babying them, as mentioned above, with the hope that with cooler weather they'll start producing again but most of my tomato FL friends yank them out in preparation of the Fall crop.
What I enjoy the most are the fresh tomatoes that a few send up to me here in the tundra for Xmas/
Dr. Jay Scott at the U of FL has developed some varieties that are supposed to do OK in FL summertime, and if you contact your nearest Cooperative Extension I'm sure they could give you some suggestions.
Hope that helps.