Sorry to say this, but we were there the 1st through the 11th. The best days were the 5th,6th, 7th & 8th! It rained on and off (not just the typical afternoon summer shower thing) for the 3-4 days before that. I remember because my DH arrived on the 5th & brought the nice weather with him. When he left on saturday the 8th, we had one more looong evening of pouring rain, I think on Sunday the 9th. The 10th was beautiful.
Last year I was in Florida from the 9th-15th, and in Disney from the 11th-15. The weather the entire time was fantastic! Sunny, warm, cooler at night. BUT, I talked with a woman on the plane who said the entire week before (the first week of march) had been cold & rainy. Her son had been at Disney
Crowds were decent both years. Moderate. Nothing like September, but nothing like July either!
So, as you can see, it's hit or miss. I wouldn't worry about it, as there's really nothing you can do. Just pack the ponchos & a change of shoes! Zip lock bags are nice for keeping money & cameras dry.