Daily
0 3 * * *
Run once a day at 03:00.
This preview is live: the table below shows the actual next run times for 0 3 * * * in your time zone, recomputed in your browser. Change the expression, dialect, or zone to experiment, then copy the result.
What 0 3 * * * means
0 3 * * * runs at 3am every day, the quietest hour on most systems and the traditional slot for heavy maintenance. Traffic is usually at its lowest, so a long-running backup or reindex has room to breathe without competing with daytime load.
Three in the morning is late enough to dodge the midnight stampede (when everyone schedules 0 0 * * *) but early enough to finish before the working day starts. It is the de facto standard for nightly maintenance across the industry.
Field-by-field breakdown
Unix cron has five fields. Here is what each one is doing in this expression:
| Field | Value | Meaning |
|---|---|---|
| Minute | 0 | minute = 0 |
| Hour | 3 | hour = 3 |
| Day of month | * | every day-of-month |
| Month | * | every month |
| Day of week | * | every day-of-week |
Every day at 3am in every scheduler
The same cadence written for the seven cron dialects you are most likely to meet. Copy the line for the system you target, the field count and day-of-week numbering differ between them.
| Scheduler | Expression | Copy |
|---|---|---|
| Unix / crontab | 0 3 * * * | |
| GitHub Actions | 0 3 * * * | |
| Kubernetes CronJob | 0 3 * * * | |
| Vercel Cron | 0 3 * * * | |
| Quartz | 0 0 3 * * * * | |
| Spring | 0 0 3 * * * | |
| AWS EventBridge | 0 3 * * * * |
When you would use 0 3 * * *
- Full database backups and integrity checks.
- Rebuilding search indexes or recomputing aggregates.
- Vacuuming, compaction, and other heavy housekeeping.
The gotcha worth knowing
In zones that observe DST, 03:00 can be skipped (spring-forward) or repeated (fall-back). A job pinned to a local 03:00 may not fire, or may fire twice, on transition night. Schedule maintenance in UTC if a missed run matters.
People also search for
0 3 * * * FAQ
What does the cron expression 0 3 * * * mean?
0 3 * * * means: Run once a day at 03:00. 0 3 * * * runs at 3am every day, the quietest hour on most systems and the traditional slot for heavy maintenance. Traffic is usually at its lowest, so a long-running backup or reindex has room to breathe without competing with daytime load.
How do I write "every day at 3am" in GitHub Actions?
Use 0 3 * * * in the schedule's cron field. In zones that observe DST, 03:00 can be skipped (spring-forward) or repeated (fall-back). A job pinned to a local 03:00 may not fire, or may fire twice, on transition night. Schedule maintenance in UTC if a missed run matters.
How do I write "every day at 3am" for AWS EventBridge?
EventBridge uses six fields with a required year and a ? placeholder in one day field: 0 3 * * * *. Wrap it as cron(0 3 * * * *) in the console or CloudFormation.
What is the Quartz equivalent of 0 3 * * *?
Quartz is seconds-first with a trailing year, so the equivalent is 0 0 3 * * * *. Remember Quartz numbers Sunday as 1, the opposite of Unix.
Related cron patterns
More cron tools
Browse the full set of cron pattern pages, or jump to the interactive tools: the cron expression builder for designing a schedule from scratch, the cron cheat sheet for a side-by-side reference, the cron timezone translator for moving a schedule between zones and dialects, and the GitHub Actions cron picker for DST-stable CI schedules.