Daylight Saving Time Transition 3/9/25

Sunday, March 9, 2025, 2:00 a.m. is the Daylight Saving Time (DST) transition from Standard Time (ST) to Daylight Time (DT). The California ISO is ready to monitor this event and ensure users experience a smooth transition.

Please review the Daylight Saving Time Short Day Information document for information on how the transition will occur in the ISO systems.

Market Timelines for the Short Day Sunday, March 9, 2025

Market Closure	Market Impacted - Day-Ahead Market (DAM), Real-Time Market (RTM)
March 8, 2025 10:00 PST	DAM (Bids, Base Schedules, RC Base Schedules) for Trading Day March 9, 2025
March 8, 2025 11:00 PST	DAM (Trades) for Trading Day March 9, 2025
March 8, 2025 23:45 PST	RTM (Bids, Base Schedules, RC Base Schedules) for Hour Ending 2:00
March 9, 2025 0:15 PST	RTM (Trades) for Hour Ending 2:00
March 9, 2025 0:45 PST	RTM (Bids, Base Schedules, RC Base Schedules) for Hour Ending 4:00
March 9, 2025 1:15 PST	RTM (Trades) for Hour Ending 4:00
March 9, 2025 1:45 PST	RTM (Bids, Base Schedules, RC Base Schedules) for Hour Ending 5:00
March 9, 2025 3:15 PDT	RTM (Trades) for Hour Ending 5:00
March 9, 2025 3:45 PDT	RTM (Bids, Base Schedules, RC Base Schedules) for Hour Ending 6:00
March 9, 2025 4:15 PDT	RTM (Trades) for Hour Ending 6:00

Contact information

Please contact ISO Service Desk at (916) 351-2309 or (888) 889-0450, or the RC West Service Desk (for RC West participants only) at (916) 538-5722 or (833) 888-9378 with any questions.