Hey, OP. Native Floridian here, who now lives in New England for the past two years. Here's my take on it:
I grew up in Jacksonville, and lived two 4-year stints in Gainesville. As you mentioned, North Florida is a bit different from the Miami/Ft Lauderdale area, but mostly in winter. It's just as hot and humid during the summer, and Gainesville usually has less breeze than Miami.
Anyway, after leaving FL the first time, I lived in NC for 5 years, then out to Colorado for a few years, then back to Gainesville for that second 4-year stint. I grew up running in that heat; it's just something we dealt with. However, coming back as an adult after many years away was absolutely BRUTAL. I'd acclimated to more moderate/less humid climates. I HATED running in FL after having been away for years; even though, as a younger guy, I had HATED running in the "freezing cold" of NC. So, it's all about perspective and acclimation.
Now, I live in New England. I've done two winters. My first one was very hard, because I'd never lived in a winter like that, even in CO. This past winter was one of the coldest in a generation, but it wasn't so bad for me. I've acclimated.
These days, when I go visit family in FL, I feel absolutely miserable. I've become one of those tourists that I used to laugh at. Of course, my family was cold when visiting me and it was 57 at night....so, it's a trade off.
My recommendation, then, for you, is that you try NOT to go back home to FL during the summers - for two reasons: 1. Once you acclimate at all to New England, FL summer is going to be f-ing miserable and 2. staying up here will help you acclimate better to the cold.
Good luck, kid!