All Events at Disneyland during May, August and December of 2016, 2020 and 2021

May 2016

Nov. 16 - TBATomorrowland : Disneyland ParkSeason of the Force Star Wars overlay, featuring Star Wars Launch Bay, Hyperspace Mountain, Path of the Jedi, and Star Wars-inspired foods at The Galactic Grill.
Early 2016 - May 6Adventureland : Disneyland ParkJungle Cruise Reopens May 6 after an extensive refurbishment.
April 1 - May 1Disney California Adventure : Disneyland ResortDisney California Adventure Food and Wine Festival Features culinary demonstrations, seminars, and new Festival Marketplaces. Festival Marketplaces are open daily; other events are Fridays-Sundays only.
May. 05 - May. 06Disney California Adventure : Disneyland ResortPixar Play Parade Returns to daily performance after its hiatus due to the Disney California Adventure Food and Wine Festival.
May. 06 - Jun. 12Hollywood Land : Disney California AdventureSneak Peak of Alice Through the Looking Glass Starting on May 6, the preview of "Alice Through the Looking Glass" will be presented in 3D with special in-theater effects at the Sunset Showcase Theater (formerly Muppets Theater).
May. 13 - Jun. 17Disney California Adventure : Disneyland ResortGrad Nites Grad Nites are a private event taking place at Disney California Adventure on select nights in May and June from 10:00 p.m. to 2:00 a.m. The dates for 2016 are: May 13, 14, 18, 20, 21, 23, 25, 31 June 1, 3, 4, 7, 8, 10, 11, 15, 17 DCA closes at 9:00 p.m. on all party evenings.
May. 27Hollywood Land : Disney California AdventureFrozen - Live at the Hyperion Opens May 27.

August 2016

Nov. 16 - TBATomorrowland : Disneyland ParkSeason of the Force Star Wars overlay, featuring Star Wars Launch Bay, Hyperspace Mountain, Path of the Jedi, and Star Wars-inspired foods at The Galactic Grill.
Jun. 16 - Aug. 13Disneyland Park : Disneyland ResortDisneyland All-American College Band This talented group of college students performs Tuesdays-Sundays for about 10 weeks during the summer. Performances are in various areas in both parks, and include a jazz set as well as marching band performances.
Jul. 01 - Aug. 14Hollywood Land : Disney California AdventureSneak peek of Pete's Dragon at Sunset Showcase Theater This sneak peek of the movie features in-theater special effects.

December 2016

http://land.allears.net/blogs/dnews/2016/09/new_merriment_coming_to_the_di.html - Jan. 08Resort Wide : Disneyland ResortHolidays at the Disneyland Resort Festive decorations resort-wide, including Christmas trees and gingerbread houses. Holiday parade and fireworks show in Disneyland, and the new World of Color - Winter Dreams and Festival of Holidays celebration in Disney California Adventure. Holiday themed versions of Jungle Cruise, Haunted Mansion, and "it's a small world". Special treats and menu items in both theme parks. Meet and Greet opportunities with holiday costumed characters and Santa Claus. Ice skating rink in Downtown Disney.
Nov. 10 - Jan. 08Disney California Adventure : Disneyland ResortFestival of Holidays Celebrate holidays around the world from November 10, 2017-January 7, 2018. Daily activities around Disney California Adventure include festival themed food and beverage booths, performances by guest musical groups, and the returning Viva Navidad! celebration.
Nov. 10 - Jan. 08Pixar Pier : Disney California AdventureWorld of Color - Season of Light This new World of Color show celebrates the season with holiday music and memorable moments from Disney animated movies.
Nov. 11 - Jan. 01Disneyland Park : Disneyland ResortPaint the Night Parade The Paint the Night Parade will return to Disneyland on select nights during the holiday season. Performance dates are currently on the Disneyland calendar are November 18-27, December 2-4, December 9-11. It's expected that the parade will run daily from December 16-January 1.
Dec. 03 - Dec. 04Main Street, U.S.A. : Disneyland ParkCandlelight Processional The Christmas story told in music and readings from the Bible. Featuring a mass choir, full orchestra, and guest narrator, performed from the Main Street Train Station. Performance times and narrators are TBD.

May 2020

No Events Announced for this Month Yet

August 2020

Summer 2020Disney California Adventure : Disneyland ResortAvengers Campus Phase 1 Opens When you visit Avengers Campus you will become part of an interconnected story that includes California Adventure, Disneyland Paris, and Hong Kong Disneyland. On each campus the Avengers will be looking for and recruiting people to join them.

December 2020

No Events Announced for this Month Yet

May 2021

April 30Disneyland Park : Disneyland ResortDisneyland Park Reopening
April 30Disney California Adventure : Disneyland ResortDisney California Adventure Reopening

August 2021

No Events Announced for this Month Yet

December 2021

Nov. 11 - Dec. 9Disneyland Park : Disneyland Resort2021 Disney Merriest Nites
Nov. 14, 2021 - Jan. 9, 2022Disney California Adventure : Disneyland Resort2021 Disney Festival of Holidays at Disney California Adventure