28 Shares People enjoy the sunshine on the top of Aspen Mountain on the first day of the summer gondola season on Friday, June 12, 2020. The gondola will be open for summer from 10 a.m. to 4 p.m. through September 7, 2020. (Kelsey Brunner, The Aspen Times) Buttermilk will open for the first time ever this year for summer sightseeing, hiking, disc golf and dining, Aspen Skiing Co. announced Tuesday. Buttermilk will open Memorial Day Weekend, May 29 to 31 and continue to be open Friday through Sunday through June 20. Skico decided to open Buttermilk because the summer operations at Aspen Mountain will be delayed until July 2 due to construction projects.