Hi David,
I like to use
www.touringplans.com when trying to judge expected crowd levels for my Disney World trips. The site uses information like past attendance, holidays, and special park events to rate each day on a scale from 1 to 10, with 10 the maximum crowds and longest wait times. I checked the site for your travel dates, and you can expect a swing in crowd sizes during your stay.
Typically most of late January into February is one of the slower periods at the parks. When you first arrive, the crowds are rated at 5 or average. You will be there for Superbowl Sunday (how cool but stake out your spot at ESPN early) and the crowds will be high that day (in the range of 8). During the following week the numbers range again around 5 and you will most likely see only small wait times except for the most popular attractions.
President's weekend will be considerably more crowded. We have been there for past President's weekends and there is a definite increase in guests coming in for the long weekend. I would certainly plan on enjoying the majority of your park time during the week and spend the weekend relaxing with some shopping, water parks or swimming at the pool.
As for the weather, the average temperatures in February are mid seventies during the day and low fifties at night, however we were there this past February that same weekend and it was in the low to mid eighties. Be prepared to dress in layers and use a light jacket in the morning and evenings.
Have a great time!