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Daylight Saving Time for Scheduled Jobs

Scheduled jobs run automatically at a fixed time, so they depend on the system clock to stay accurate. Daylight Saving Time (DST) shifts that clock forward or back twice a year, and any job scheduled to run during the shift can be affected. Depending on the exact time, a job can run early, late, twice, or not run at all. Schedule jobs outside DST transition windows whenever possible to avoid these issues.

note

The exact timing and length of the DST change vary by region.

ExampleIssues during DST transition for the United States#
Scenario

In the United States, DST changes happen on Sundays between 12:00 a.m. and 3:00 a.m. Jobs scheduled within that window can encounter the following issues:

Details

A job that is scheduled:

  • At 1:05 a.m. can run twice when DST ends.
  • At 2:05 a.m. can skip its run when DST starts.
  • Every 30 minutes between 12:00 a.m. and 3:00 a.m. can run two extra times when DST ends.
  • Every 30 minutes between 12:00 a.m. and 3:00 a.m. can skip two runs when DST starts.
Keep in mind

Schedule jobs outside this window when possible.