Re: Learn to sail this winter: Where to go?
With the exception of schools in Florida and So. Cal, I think you'll find that most sailing schools in the U.S. hold their winter classes out of the Caribbean.
If you aren't committed to a winter timeline, I would suggest finding a good ASA program in the waters you are likely to be sailing in come spring, and practice all season long. (I know Florida winters are supposed to be warm, but every time I'm down there, it's even colder than DC.)
1987 Pearson 28-2, Deale MD