my family used to go in mid - end may. 2 years ago we went the first week in June. The crowds were very manageable both times. Big rides usually need some fastpasses but still manageable if you get there early enough. The weather was very hot but not extremely humid. Sunscreen is your friend! Ha! My boyfriend and I are going the last week of may (21-28) and looking forward to beautiful weather (hopefully) and low crowds (hopefully). But hey, we're in Disney. We will make the best of crappy weather and high level crowds if we must. Have fun!