Walt Disney World's website has revealed details of planned ride refurbishments to be carried out this winter.
At the Magic Kingdom, Splash Mountain will be closed from January 3 through February 27, while The Magic Carpets of Aladdin is due to be out of action from December 6-19. Space Mountain should return from its prolonged refurbishment on November 22.
Walt Disney World's water parks will both shut down completely for annual refurbishment work. Typhoon Lagoon will be shuttered between November 1 and January 9, while Blizzard Beach will be closed from January 10 through March 20.
Disney regularly updates its operational updates page to show planned ride closures, with the list showing planned "rehabs" over the next six months. Note that while Disney generally publishes these well in advance, it is not uncommon for rides to be closed at short notice.
You can keep up-to-date with the latest confirmed and rumored temporary ride closures through Theme Park Tourist's "Rehab Watch".