We were there last year the same time.
Crowds were very manageable. Sometimes it looked like it was more crowded then it actually was. We stayed onsite so we had the express passes and rode everything with no waits at all but most rides only had 15 minute waits without the express pass except for the Minion ride which had a 30 minute wait.
Weather was wonderful. We had one chilly day where it was only around 68 degrees and a bit rainy. Rest of the time it was upper 70's to low 80's.
It was really a perfect time to go and we plan on doing it again next year so I can see the new Harry Potter expansion.