Cron expression for Every 6 hours
0 */6 * * *
Runs four times a day, at 00:00, 06:00, 12:00 and 18:00.
Next 5 runs (your local time)
These are shown in your browser’s timezone. The job itself runs in the scheduler’s timezone — often UTC — so the real run time can differ.
What people actually schedule with 0 */6 * * *
- Full backups of small-to-medium databases (dailies as a floor, 6-hourly during launches)
- Certificate renewal checks, certbot-style — frequent enough to never miss a window
- Pulling reference data: currency rates, weather, geo databases
Use 0 */6 * * * on your platform
It’s the same 5-field expression everywhere — what changes is where you put it and which timezone it runs in.
Linux / crontab
0 */6 * * * /path/to/your-commandRuns in the server’s local timezone — check it with timedatectl.
Full field reference: crontab(5) man page.
GitHub Actions
on:
schedule:
- cron: "0 */6 * * *"GitHub Actions always runs scheduled jobs in UTC — there is no timezone setting, and runs can be delayed under load (official docs).
Kubernetes CronJob
spec:
schedule: "0 */6 * * *"Defaults to UTC. Set spec.timeZone (Kubernetes 1.27+)
for a specific zone — see the
CronJob docs.
Quartz / Spring @Scheduled
Quartz uses 6 fields (seconds first): 0 0 */6 * * *. Watch out:
Quartz day-of-week is 1=SUN … 7=SAT (not 0–6), and day-of-month /
day-of-week use ? — double-check if your schedule touches those fields
(Quartz cron reference).
Gotchas with every 6 hours schedules
- The 00:00 run lands on the global midnight spike.
0 3,9,15,21 * * *keeps four-a-day and skips the rush. - “Four times a day” happens in the scheduler’s timezone — on a UTC box that’s 08:00/14:00/20:00/02:00 in Taipei. Write the intended local times in a comment next to the cron line; future-you will thank you.
Will you know if this job silently fails?
Cron jobs fail quietly — a server reboots, a path changes, or an error code is ignored — and nobody notices until the data is missing. A cron monitor (a dead-man’s-switch) alerts you when a scheduled job does not check in on time.
Monitor your cron jobs with UptimeRobot →
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Is 0 */6 * * * the right schedule?
Storage tight? Every 12 hours. Compliance asks for more retention points? Stay here before jumping to hourly — that’s 6× the storage for data nobody restores.
Or use the interactive cron generator & explainer, read the complete cron syntax guide, or pick another common schedule: