Daylight Saving Time Transition 11/2/25

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

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

Market Timelines for the Long Day Sunday, Nov. 2, 2025

Market Closure	Market Impacted – Day-Ahead Market (DAM), Real-Time Market (RTM)
11/01/2025 1000 PDT	DAM (Bids, Base Schedules, RC Base Schedules) for Trading Day 11/02/2025
11/01/2025 1100 PDT	DAM (Trades) for Trading Day 11/02/2025
11/01/2025 2345 PDT	RTM (Bids, Base Schedules, RC Base Schedules) for Hour Ending 0200
11/01/2025 0015 PDT	RTM (Trades) for Hour Ending 0200
11/02/2025 0045 PDT	RTM (Bids, Base Schedules, RC Base Schedules) for Hour Ending 0200* (Second Hour Ending 0200)
11/02/2025 0115 PDT	RTM (Trades) for Hour Ending 0200* (Second Hour Ending 0200)
11/02/2025 0145 PDT	RTM (Bids, Base Schedules, RC Base Schedules) for Hour Ending 0300
11/02/2025 0115 PST	RTM (Trades) for Hour Ending 0300
11/02/2025 0145 PST	RTM (Bids, Base Schedules, RC Base Schedules) for Hour Ending 0400
11/02/2025 0215 PST	RTM (Trades) for Hour Ending 0400

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.