Welcome aboard, Erika! My family and I have sailed with Disney Cruise Line at all different times of year, and have had magical adventures each time!
While it is true that it is warmer in the summer than any other time of year, I'd not hesitate to book another summer sailing at all! The entire ship is air conditioned, to the point that I always bring a light jacket or sweater with me, even in August, to keep warm when we head to dinner or the shows, as I get chilly easily.
On deck, there's plenty of shade, and of course refreshing
pools and the AquaDunk to cool you off when weather gets warm! My kids would probably mention cooling off with free soft serve ice cream all day too! On
Castaway Cay, the beach is amazing, the water is super refreshing and there are so many water related activities, plus plenty of shade from trees and the hundreds of umbrellas lining the beach!
Each of the ports of call in the Bahamas and Caribbean offer
Port Adventures, many of which include water activities to cool you down as well! Now, I will say that in Cozumel, we found the adventures to the ruins really worthwhile to visit, but very hot, no matter what time of year, but besides that, it's been warm but wonderful!
At night, and while at sea, there is always a breeze that can be a bit chilly, especially in the evening, so I do recommend a sweater even in summer.
I hope that you book a magical adventure with Disney at sea. Captain Mickey and his crew have so much in store with something for everyone both onboard and in the ports of call, Erika! You won't regret it! Please stop back if you have other questions as you continue to plan. We're happy to help!
Marcy