Horses are amazingly adaptable.
My WB was bred in Queensland, Australia - climate like FL.
Imported to FL at 6, I brought him to the frigid Midwest when he was 15.
He arrived December 1, showslick, with just a cotton sheet.
I put my 78 midweight blanket on his 84 self. Plumbers Butt
I had him 5 years & he never got more than plushy in Winter & never needed a blanket.
His pony companion- bred & raised here - became a yak, WB hardly hairy
We get some hot & humid Summers w/90s for days.
I’m a walking sweat ball, horses never seem overly sweaty