We went for the weekend Jan 21-23, 2005. Sat. was nice, light jackets for evening, we wore flip flops... here's a pic:
Sun. a cold front came through. Wore coats at MK all day, riding the TTA was brrr chilly! Here's a pic:
Mon. morning it was really, really cold! But hey, we were at WDW! At home, they got 8" of snow that weekend...
Crowds were nonexistant, no ride waits, though we could not walk up and get a table for dinner at Le Cellier... I don't think you can ever do that again, it's too popular now. We had ressies for Chef Mickey's before we arrived for my dd's birthday, that was the only place the kids requested. We did counter service the rest of the time.
We went in Feb. 2002 and it was warmer. As long as you don't go during MLK or Presidents Day holidays the crowds will be low that time of year.