WooCommerce timezone offset discrepancies in Action Scheduler execution

Execution Logic and Timezone Handling

Action Scheduler does not resolve conflicts by syncing with the WordPress site timezone; instead, it avoids them by operating exclusively in UTC. All scheduled event timestamps are stored in the database as UTC, and the execution engine compares these against the current UTC time provided by the PHP environment.

The WordPress site timezone setting (configured in General Settings) is a presentation layer preference. It dictates how dates are displayed to the administrator but has no influence over the internal logic that triggers a scheduled task. Consequently, there is no configuration to make Action Scheduler "respect" a local offset, as doing so would introduce instability during Daylight Saving Time transitions or server migrations.

Likely Cause of Execution Drift

When tasks trigger at unexpected intervals despite correct UI settings, the discrepancy is typically not a WordPress configuration issue, but a server-level synchronization failure. If the server's system clock drifts from the actual global UTC, the PHP environment's time calculations will be offset, causing Action Scheduler to perceive tasks as either overdue or not yet due.

Steps to Synchronize and Verify

1. Verify Server UTC: Access your server via SSH and run the following command to check the current system time in UTC:

   date -u

   Compare this output with a reliable atomic clock. If they differ, you must synchronize your server using NTP (Network Time Protocol).
2. Inspect Database Timestamps: Check the scheduled_date_gmt column in the wp_actions_scheduler_actions table. Confirm that the dates stored there align with the intended UTC execution time, not your local timezone.
3. Rule out WP-Cron Latency: If tasks are delayed but eventually run, the issue is likely WP-Cron latency rather than a timezone offset. WP-Cron only triggers when a page is visited. For high-precision execution, replace the default cron with a system-level cron job that calls wp-cron.php every minute.

Required Diagnostic Detail

To determine if the issue is clock drift or cron latency, please provide the output of date -u from your server and confirm if you are using the default WordPress cron or a server-side cron job.