Cron every hour

0 * * * * runs a job once an hour, on the hour. Most cron implementations also accept @hourly as a shortcut for exactly this.

Why the zero matters

The first field is the minute. 0 pins it to minute zero, so the job runs at 10:00, 11:00, 12:00. A common mistake is * * * * * or * */1 * * *: both run every minute, because the minute field is still *.

When it fires

Checked at 09:58 UTC, the next five runs are:

10:00  11:00  12:00  13:00  14:00

To run at a different minute past each hour, put it in the first field: 17 * * * * runs at 10:17, 11:17 and so on. Picking a minute other than 0 spreads load away from the top of the hour, when many jobs start at once.

The same schedule elsewhere

• GitHub Actions: cron: '0 * * * *'. Runs at the top of the hour are the most likely to be delayed, so another minute is often better.
• Kubernetes CronJob: schedule: "0 * * * *", or "@hourly".
• AWS EventBridge: rate(1 hour), or cron(0 * * * ? *).
• systemd timer: OnCalendar=hourly.
• Spring @Scheduled: 0 0 * * * *.