My favorite time for World Showcase is when it opens at 11 a.m. That's the least crowded time of day to be there, as the crowds pick up as the day goes on, most notably around dinner time. We normally go during the off-season, so heat isn't a factor. The one time we did visit during hot weather (mid-May), we happened to be in Future World in the afternoon, and all that walking from one pavilion to another in the brutal sun about did me in!