When we went in 2015, we were there May 16-22 (third week). If I remember correctly there was a chance of rain pretty much every day, but I can only recall rain happening once or twice while we were at the parks (a super short rain one afternoon and once overnight). The temperatures were mid 70s-mid 80s and I honestly couldn't tell you how humid it was. Since I live in the south right now, it doesn't really get to me as I am used to it. My husband was sweating, but the girls didn't complain. Not sure if that gives you an idea. I wore sundresses everyday and felt fine. The crowds weren't too bad in my opinion. We had good luck with fastpasses and I want to say the longest we waited for a ride was maybe 50 minutes. Usually the lines were closer to 30-40 minutes. We made it to the last day of EPCOT's Flower and Garden Festival. We loved all of the flowers and topiaries. They made for great pictures. We also enjoyed trying some of the dishes available at the food booths. It is a great time of year to visit. Not oppressively hot or crowded yet. For the past year it seems like the slow times have not been as slow as they once were, so I am not sure if that will change the crowds for that time frame this year as well. We would love to go mid May again, but now we have kids in jr high and it doesn't seem as easy to pull them out of school as it did when they were in elementary school.