We went last year - 2/9 - 2/15. DEFINITELY pack long pants, light jacket, sweatshirts. But, t-shirts, shorts too. In other words, it goes either way. One day it was 75 and sunny, the next day 55-60 and cloudy and windy. Chilly at night! In fact, we only had one good weather day during our whole stay. The rest of the time it was chilly and/or windy, gray, overcast, damp, and cool. Some days were tolerable - 65-ish. But, I wasn't very happy with the weather. Some people like it that way but I like Florida the way it is intended to be. The pools are heated, but when you get out, BRRRRRRR.
PamNC