I live in Boca Raton which is about 30 minutes south.
We have had many Thanksgiving days where we could easily seat guests outside and have it be pleasant.
I usually stop swimming in the ocean by the end of October, but many people are still in the ocean in November.
Christmas week up through New Years can be a little more dicey. We have actually had some cold snaps hit in January where we get down in the high 40's - which down here is VERY cold. On the other hand it could be hot like summer. You just never know. Also, Christmas week through New Years is THE most crowded time down here. So it's a little harder to go to the movies, out to dinner, etc.
Thanksgiving is one of my favorite times here. That's just something cool about hanging by the pool yet having all the turkey and fixin's.
For things to do the kids would probably love Lion Country Safari which is in Loxahatchee (west of West Palm).
The adults may like to visit the Flagler Museum in Palm Beach (it's a former Flagler home). The kids may even like it depending whether they like museums.
If I think of more cool things to do I will message you!