We went last April/May and the weather was superb. Only ever wore t-shirts but I would recommend taking a long sleeved top just in case. 2 cloudy days all of the fortnight were still warm. Just a warning though, on these two cloudy days it rained! Oh boy it rained like I've never seen before! However, just as quickly as the rain arrived, it went away again. The crowds were small too. The longest we had to wait to get on any of the rides was 20 minutes and that was rare especially if you use fastpass.
Hope this helps, you'll have the time of your life.