Hi Rebecca,
March usually is one of the most pleasant weather months in Florida, with highs in the upper 70s and lows in the 50s. It can occasionally turn cool, so be sure to bring a jacket, just in case.
March is a popular time at Walt Disney World because of the great weather, Spring Break, the Epcot International Flower and Garden Festival and the Atlanta Braves spring training at the ESPN Wide World of Sports Complex. The weeks before and after Easter (March 31 this year) are generally among the busiest in the spring.
Because it is more crowded in March, I would recommend that you make
advanced dining reservations for any restaurants or character meals you don't want to miss. If you are staying on Disney property, you also should take advantage of
Extra Magic Hours to maximize your time in the parks.
Unfortunately, it appears Blizzard Beach will be closed for refurbishment during your stay, but
Typhoon Lagoon has already gotten its annual facelift and will be open.
I'm sure you will have a great visit. Please let me know if I can answer any more questions for you. Enjoy your time with your family!
Wilma