In 2003 we did the week before President's Day (leaving the Saturday of President's Day weekend). Up until the Friday of that weekend most rides were walk-ons. Really, on several rides we were the only one's even attempting to get on. It was actually alittle eerie!
The weather however wasn't swimming warm. Only once it made it out of the 60's. Even then it was only like 72-73. Most days were 65-68, but very sunny and dry. Our entire 8 days was really gorgeous, we only saw rain our arrival day. The lows were in the upper 40's so nights did require pants and coats. However, for touring the parks it really was perfect weather.