Reservations should be made well in advance as park lodging tends to be full most of the year.
South Rim Grand Canyon Village Lodging is open all year
South Rim Desert View (24 miles east of Grand Canyon Village) is open all year - Lodging is not available at Desert View. However there is a "first come, first serve" campground that is closed for the winter. Desert View Campground will be open from mid-April through mid-October 2019. (No hook-ups at Desert View Campground)
North Rim Lodging is Closed for the Winter: Lodging is available May 15th through October 15 of each year.
Phantom Ranch at the bottom of Grand Canyon - is open all year.
Reservations can be made through an online lottery system. More.