Looking to go to Florida in late December but I notice from looking at temperatures that it can be 63-70 degrees fahrenheit in many of the places. I saw some nice spots in Destin but looks too cold at this time.
Does anyone have any suggestions for a vacation spot in Florida where average temperatures are above 75 Fahrenheit?

Miami Beach or the Keys.

We've gone to Cocoa Beach for the past 4 or 5 years mid-December and had warm weather each time. I think it's a fluke and we're gonna get stung real soon, but for now we keep going back.

The further south you go the better the chance for warm weather. Florida, however, in December is a gamble. It can get real cool. I stopped going to Florida in December for that reason. December vacations are now taken in the Caribbean - it is always warm to hot and you can go swimming every day.

Destin is a summer destination, too cold for swimming in December. For best chance of warm, swimming weather, look from Sanibel/Captiva on down. Clearwater and Sarasota will usually have temps in your range too, but there is a chance of a cold front sneak in. This past Christmas our beaches (Clearwater/St Pete) were warm and crowded with plenty of people swimming, but that might not always be the case.

Heather:

It is a crap shoot when it comes to December weather in Florida. Even in Ft. Lauderdale/Miami/Keys there can be a cold snap for 2 or 3 days. However, a cold snap in Ft. Lauderdale and the surrounding area is 65F. I'd say the average temp there though is 75+. No matter what it will really seem warm if you are coming from the NE.

Last winter I tracked the weather daily for several Florida cities to find the best place for the winter. The temps varied depending on storm systems etc., but the best bet seemed to be around Naple and below. Only problem I saw is FL tends to be $$$ in the winter.