January is a great time to visit Florida. It us normally nice weather (70's I believe although it can range quite a bit - w have had 80 degree days in Jan.) You can swim (all pools at Disney are heated). You will need to pack for both warm and cool weather though as days are usually mild, but nights (and early mornings) can get quite cool. The lines at the parks are short then too. All in all, January is quite nice.
As Hawkshoe said it's a great time to go. The average temperature is high 70 with nighttime lows 50. The Disney pools are heated so if you don't mind cooler air temperatures your O.K. with swimming. The 1st week of January can still have the left over holiday crowd though so if you schedule allows it I would plan on coming the 2nd week of January through the 1st week of February when it is Disney's least crowded time!
Thank you both very much for the info. It is good to hear that the pools are heated. I am probably a lame-o for asking this but..does that mean that the water parks have heated water there to? Thanks for the advice about the first week of Jan. that was when we were thinking of going so we will change that to the 2nd or middle of Jan. Thanks!!