We go to Disney in late January as a rule and although it is usually colder than most people would like (high 60’s-low to mid 70’s), you can  enjoy the parks so much easier than at other times of the year.  Last year my children were obsessed with Buzz Lightyear’s Space Ranger Spin, and we rode it 15 times in a row with no waiting.  We were also able to experience Test Track multiple times. Just be sure to check for the WDW Marathon, as that weekend can get busy.