https://www.gamespot.com/articles/psa-destiny-2-weekly-reset-time-changes-starting-t/1100-6455391/

Today marks a big day for Destiny 2, as the game's first major DLC expansion, Curse of Osiris, is now available on PlayStation 4, Xbox One, and PC. Almost as important, today also marks a change in Destiny 2's weekly reset schedule.

Beginning today, December 5, Destiny 2's weekly reset will occur at a different time going forward. Up until now, the reset would happen at either 1 AM or 2 AM PT; now, however, it will take place every Tuesday at 9 AM PT. You can see the new schedule for various time zones below: