What is the average temperature in Orlando, FL in January and would it be possible to attend any water parks?
It may be still a cool month between 21C degrees during the day and sometimes falls down to 9C at night. You better check online but I remember that I went to Orlando theme parks in January and it was pretty cold. However, I must say that I am from a tropical country and not very fan of cold weather.
We do get winter here in January. I would say be prepared for a mixture of warm days and cool nights. Its been known to dip down to the 30's or 40's at night. I would bring a hooded jacket or sweater to layer if needed. Not all of the water parks are open in the winter, so check online before you come down on your vacation.
When we've done Disney in Jan. it's always been 70's and 60's at night. I'm from New England so the pools and water parks work for us as long as we do them in the early afternoon when temps are at there highest.