Every Sunday cron: what 0 9 * * 0 means and why Sunday is 0 and 7

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Updated Oct 8, 2026

Example

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Cron expression (sample)

Five fields — minute, hour, day of month, month, day of week. Macros like @daily are supported too.

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Timezone

fig. 04 — cron-expression-tester · scheduling Valid

Result

At 09:00, on Sunday.

Minute0

Hour9

Day of month*

Month*

Day of week0

Next runs

Computed in your browser, in your timezone.

`0 9 * * 0` fires once a week, at 09:00 on Sunday. The engine reads it as: At 09:00, on Sunday.

Sunday is 0 (and usually 7)

Standard cron numbers the week from Sunday = 0 to Saturday = 6. Most implementations, including Vixie cron and cronie, also accept 7 as Sunday so that ranges like 1-7 read naturally as Monday to Sunday. 0 9 * * 0, 0 9 * * 7 and 0 9 * * SUN are therefore the same schedule on those systems; 0 is the most portable choice.

The parser on this page reads the expression as: At 09:00, on Sunday. The next run times in the panel above are computed in your browser, in your own timezone, so they are not printed in this text.

Sunday maintenance windows

Sunday morning is a traditional low-traffic slot for heavier maintenance: database VACUUM or index rebuilds, full backups, OS patching with a reboot. 0 9 * * 0 flock -n /run/lock/weekly-maint.lock /opt/ops/bin/weekly-maintenance >> /var/log/weekly-maint.log 2>&1 is a typical shape. Long jobs are exactly the ones that overlap, so the lock earns its place even on a weekly schedule.

Low traffic for your users depends on where they are. 09:00 Sunday UTC is Sunday afternoon in Asia and Sunday early morning in the Americas, so pick the hour from your traffic graphs, not from the calendar.

Timezone and daylight saving

Many zones change their clocks on a Sunday, typically in the early hours. A job at 09:00 is clear of the transition itself, but if the server follows local time the run moves an hour relative to UTC on those weekends. If it has to line up with something scheduled in UTC, such as a provider's maintenance window or a GitHub Actions workflow, keep the server on UTC or pin the zone with CRON_TZ or a Kubernetes timeZone.

systemd, Kubernetes and GitHub Actions

systemd: OnCalendar=Sun *-*-* 09:00:00. Kubernetes: schedule: "0 9 * * 0". GitHub Actions accepts 0 9 * * 0 and runs it at 09:00 UTC. If you want Sunday at midnight instead, that is what the @weekly macro means; every Monday is the start-of-week counterpart.

FAQ

Questions, answered.

Tap a question to expand the answer.

Should I use 0 or 7 for Sunday?

Use 0. It is defined by POSIX cron and accepted everywhere, while 7 is a common extension that some minimal cron implementations reject.

How do I run on both Saturday and Sunday?

List both days in the day-of-week field: 0 9 * * 0,6, or 0 9 * * SAT,SUN.

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