Hi, Lesly!
Truly, any month of the year is a great one to cruise aboard Disney Cruise Line! If you're thinking of taking a Bahamian or Caribbean cruise, you really aren't limited with your choices -- with the exception of Caribbean cruises for this summer. The ones around Europe, the Mediterranean, the Alaskan Coast and the Pacific Northwest and the Mexican Riviera are offered seasonally, and you'll have to compare your schedule with what's available more closely.
For the Bahamian cruises which sail out of Port Canaveral, Florida, I like cruising when it's usually cold in the US -- December, January and February. It helps me get through the winter, and there's nothing like packing your swimsuit and shorts instead of all those ski clothes and equipment.
As far as
Port Adventures I recommend, it's (of course) going to depend on what itinerary you choose and for how many days/nights you select. For Bahamian cruises, the Atlantis Aquaventure and the Blue Lagoon Island Dolphin Encounter are of the most popular, and on Castaway Cay, many guests enjoy the stingray experience as well as renting various watercraft, bicycles, snorkeling equipment and inner tubes for the day.
I hope this helps you plan. Have a wonderful day and a magical vacation. Bon voyage!
Andi