The weather has been quite bad for the past several days. Deadly lightning, hail and high wind storms that have done damage and knocked out power to some surrounding areas of WDW. This has alternated with "regular" summer rains that are not cooling things off a bit, when they end.
Yesterday, for example, right at rush hour, when I-4 was backed up from Lake Buena Vista to Lake Mary Blvd. (hour delay) due to rush hour traffic, and many folks attempting to get to Daytona for the Winn Dixie 250, there was a wicked storm with much deadly lightning. Not nice to be caught in at all.
Can't say as though we are having much of a summer yet this year, with this sort of weather.
The sun is shining now, however so there are parts of the days that give you some good weather. If you've not done what you want to do by eleven a.m. or noon, plan on doing it in the rain, and possibly nasty, stormy weather.
Be certain to bring rain gear with you. The ponchos aren't going to cut it in this type of weather. And don't forget back up dry shoes.