Curated cron expression
Daily at 3 AM Cron Expression: 0 3 * * *
0 3 * * * — off-peak nightly maintenance window — with platform compatibility.
Meaning at a glance
0 3 * * *
Run every day at 03:00
Once daily at 03:00.
Next-run example: At 22:00, next run is 03:00 tomorrow.
How 0 3 * * * works
Three AM is a common maintenance slot with lower user traffic.
Ensure timezone matches the region you optimize for.
Preview next runs and platform conversions in CronWizard before deploying to production.
| Field | Value | Meaning |
|---|---|---|
| Minute | 0 | Configured as 0 |
| Hour | 3 | Configured as 3 |
| Day of month | * | Every value |
| Month | * | Every value |
| Day of week | * | Every value |
Good use cases
- Database vacuum
- Log rotation
- Backup jobs
Timezone and daylight-saving behavior
Document whether 03:00 is UTC or local.
Spring-forward can skip 02:00–03:00 window in some zones.
The expression does not contain a timezone. The scheduler supplies that context. Use the next-run preview above in the same IANA timezone as production, then confirm the target platform's own timezone rules.
Platform compatibility and converted expressions
The source expression is five-field Unix cron. Use the exact equivalent below rather than adding or removing fields by sight.
| Platform | Status | Expression | What to know |
|---|---|---|---|
| Unix crontab | Ready | 0 3 * * * | Use directly in a normal five-field user crontab. |
| Kubernetes CronJob | Ready | 0 3 * * * | Use as spec.schedule; set spec.timeZone when local wall-clock behavior matters. |
| GitHub Actions | Ready | 0 3 * * * | Use under on.schedule; UTC is the default and an IANA timezone may be specified. |
| Vercel Cron Jobs | Plan / behavior limit | 0 3 * * * | The expression is valid, but Vercel always uses UTC and Hobby schedules run at most once per day. |
| AWS EventBridge Scheduler | Convert | cron(0 3 ? * ? *) | Convert to AWS minute-first cron(...), add the required year, and use ? in one day field. |
| Spring @Scheduled | Convert | 0 0 3 * * * | Use Spring’s six fields by prepending seconds and set zone explicitly when needed. |
| systemd timer | Convert | 0 3 * * * | Use OnCalendar syntax and validate it with systemd-analyze calendar on the target host. |
Edge cases to check before deployment
- Long jobs may overlap next day's window.
Frequently asked questions
What does the cron expression 0 3 * * * mean?
0 3 * * * means “run every day at 03:00.” Once daily at 03:00.
What are the next run times for 0 3 * * *?
At 22:00, next run is 03:00 tomorrow. Exact timestamps depend on the scheduler timezone and the current time.
What timezone does 0 3 * * * use?
Document whether 03:00 is UTC or local.
Can I use 0 3 * * * on every scheduling platform?
No. It is a five-field Unix expression. Some platforms accept it directly, while AWS EventBridge Scheduler, Spring, and systemd require the converted form shown in the compatibility table.