Depends on how chilly of course. But this time of the year, I'd guess most of the crowds during the week days will be travelers coming in from outside the Orlando area. That means unless it is really really colder, they will probably still hit the parks as they already paid to be here. I'd guess you might see a bit of reduced crowds (over normal) during the weekends where more of the local crowds hit the parks who may not come as much if the weather isn't as nice as the next weekend could be.
But overall, if the weather is cold, but dry, I'd expect to see the crowds still come.