Hi Stacia,
Thank you for visiting the Disney Parks Moms Panel with your question. I am happy to help you think about your January trip to Walt Disney World!
I think that the middle of January is a great time of year to visit Walt Disney World. Since there are not too many major school breaks at that time, you should find the number of guests at the theme parks lower than it would be during a peak time of year. You might find that right around Martin Luther King, Jr. Day, which is January 15 in 2018, there might be a slight bump in attendance for the three-day holiday weekend, but it will not be as much as over Spring Break or the winter holidays, for example.
As to temperature, you should find the average high temperatures to be in the low 70's Fahrenheit. This is wonderfully comfortable for touring theme parks. It can be a bit chilly for swimming; however, Walt Disney World does feature heated swimming pools at their resort hotels, so the water will be warm. It can just be that walk back to your room that gets chilly! If you have little ones, you may find that the pool is irresistible. When my daughter was in preschool and we visited Walt Disney World in December, I was in the pool with her multiple times!
If you do choose to visit Walt Disney World during mid-January, check out the
Epcot International Festival of the Arts. This relatively new and fun festival celebrates the arts in exciting ways.
I hope that this information is helpful for you, Stacia. Please do let us know if you have any further questions.