Hi Amy!
It is a great idea to have as much information in hand about the parks and attractions so you can plan for your upcoming Walt Disney World vacation. By being as aware as possible of closed attractions you can prevent the sad faces when you enter and see the signs stating what is not operating.
All of the park attractions must under go refurbishment from time to time. Some attractions need more attention then others due to being water rides or heavy use rides. Disney keeps a plan in place so only one ride or so is down at a time. This prevents guests from being upset from too many things being closed. But we all know that sometimes the attractions don't follow the rules and have breakdowns or areas that need unexpected attention. Disney cannot always know when that will happen.
The best thing to do is to refer to the
Attraction page on the website. At the end of this list of Disney park attractions you will find a list of the ones that are closed for refurbishment. Disney will not publish specific dates but you can click on a closed attraction and they will give you a vague idea of when it might reopen.
Since holidays are very busy Disney will try to have as many attractions up and running as possible. Right after New Years will be a time that they will start again with refurbishments. You might be lucky to get in under the holiday time or things might go down fairly quickly. Just keep watching the website list before you arrive. When you check in your resort concierge can also check the latest news for you before you head to the parks.
Have fun! It should be a great time for a Disney visit!