Cron Every Sunday at 3 AM

The cron expression 0 3 * * 0 schedules a task to run once per week on Sunday at exactly 3:00 AM.

Field-by-field breakdown:

• 0 (Minute): At minute 0. The task fires at the top of the hour.
• 3 (Hour): At hour 3 (3 AM). The task runs during the deep overnight window when system usage is typically at its lowest.
• * (Day of Month): Every day from 1 through 31. No restriction on the day of the month.
• * (Month): Every month from January through December. No restriction on which month.
• 0 (Day of Week): Sunday only. The value 0 represents Sunday in standard cron.

This means your task will execute once per week, every Sunday at 3:00 AM server time. Sunday at 3 AM is widely considered the optimal window for heavy weekly maintenance. It combines the lowest-traffic day of the week with the lowest-traffic hour of the day, creating the maximum resource availability for intensive operations. This is the ideal time for tasks like full database vacuuming, storage cleanup, weekly security audits, or rebuilding large search indexes. The early Sunday timing ensures that any issues can be detected and resolved well before Monday business hours. This expression is supported by standard cron on Linux/macOS, as well as cloud services like AWS CloudWatch, Google Cloud Scheduler, and GitHub Actions.