Just my observation on FL mosquitoes. The population varies with recent rainfall history. If you get substantial rain after a dry period then the skeeters will swarm as the eggs hatch out. The population will generally drop to a base level after repeated rain days. Nothing scientific in this but just observations over decades down here.
That said we spent 10 days down there in the summer and I didn't notice any exceptional population of mosquitoes. DEET will mostly keep them off.
The worst mosquito swarm I've ever seen was when I camped out in upper Wisconsin. The fact that it was one of my first camping trips and I was trying to sleep in a tube tent (anyone remember those) may have influenced my perception tho. The second worse was in Ochopee, FL tho. Right on the edge of the Everglades.