We've been in mid-April twice, and the weather was perfect...sunny and warm, but not too hot. We wore shorts to the parks, were able to swim, and I think between the two trips, we only had one evening where there were some really heavy rain showers. However, they cleared in time for the evening fireworks shows. We didn't think the crowd levels were too bad either, except for one really heavy Sunday at MK. Sometime in April, Disney starts having Grad Nights that close MK on Friday and Saturday nights early with no Spectromagic or Wishes. Don't go to MK on Sunday after Grad Nights...way too crowded.