The crowds have always been easily navigated on my 6 trips the firdt two weeks of May. I generally stay away from surprise mornings and that has worked well. Epcot has never been crowded. The Studios and Animal Kingdom have been moderately crowded but the most I have waited for anything was 15 minutes. If you do the most popular attractions first the rest of the day is a breeze. The Magic Kingdom has been fine on its non early entry days and on week days. On ealry entry day it was quite a bit more crowded but still not unbareable. However Saturdays at the MK have always been fairly packed. In the past Saturday was always the early entry day. Last yeat that changed but it still seemed really crowded. Many times during May the Fireworks and Spectro Magic parade only showed on Saturday which will also increase the crowds but if you want to see them you have to go that night...along with everyone else who has a trip that week.
The weather has gone from being in the high 70's to low eighties on one trip to changing from the low eighties to the mid nineties and on two trips it was in the mid nineties everyday. It has been fairly humid to slightly humid on the days with lower temps. It hardley ever has rained. Two of my trips it didn't rain at all. two trips it rained just a bit on one day and two trips there were hour long storms a couple times during the week.
I personally love May because the weather is warmed and the nights stay in the high 60's to high 70's. The slowers are blooming eberywhere and Epcot has the flower and Garden Festival which is very pretty.
