We were there last May at that time and I remember it being the hottest May in FL in years, it was REALLY HOT, but there wasn't a drop of rain.
We'd go to the parks for a few hours in the morning, have lunch and head back to the resort to hang out in the pool. At least we didn't have to deal with those "afternoon showers" that typically hit from June through Sept.
The crowds were very managable, definitely the calm after the storm
Even our resort was very quiet and many times we practically had the pool to ourselves.
It was hot, but I'd go again at that time, oh hey, we are going then, how about that! We'll actually be checking out when you're checking in.
Enjoy, this is a nice time to go to WDW!