Disney World is a popular destination all year round, especially during the holiday season. The amusement park knows that people plan trips to their park many months in advance and they want to make sure they can accomodate all the tourists coming to visit.
As you might expect they are open 365 days a year and even have special events if you are there during the holidays. You can go directly to their calendar to help plan your next trip by visiting: https://disneyworld.disney.go.com/calendars/month/