Kristina:
Afternoon showers in Florida are a part of the climate, and rain will not shut down the water parks nor make you eligible for a rain check. Just like the theme parks, slides and attractions will remain open. I welcome rain when we're at
Blizzard Beach or Typhoon Lagoon because many guests exit the parks, leaving fewer crowds with which to compete for the chairlift!
Thunder and lightning are a different story. Slides will be shut down and guests will be asked to exit the water when thunder and lightning are seen in the area. Safety is very important to Disney, so you won't be allowed to return to the water until all is clear. The park will not close, however, and you are welcome to enjoy the restaurants, shops and beach in the meantime. Generally, if inclement conditions persist and the park closes with less than 4 hours of attractions being open that day, you'll be eligible for a rain check.
Wishing y'all a dry, magical vacation!
Whitney