Cron monthly on the 15th at midnight: the expression, explained, in WordPress

The cron expression for “monthly on the 15th at midnight” is 0 0 15 * *. This page shows what each field does, the next five times it will fire, the mistake most people make with it, and a working WordPress example you can paste.

The expression

0 0 15 * *

Field	Value	Meaning
minute	0	exactly 0
hour	0	exactly 0
day of month	15	exactly 15
month	*	every month
day of week	*	every day of week

Next five runs (UTC, from now)

2026-10-15 00:00 UTC
2026-11-15 00:00 UTC
2026-12-15 00:00 UTC
2027-01-15 00:00 UTC
2027-02-15 00:00 UTC

Mistakes people make with this schedule

Adding a day-of-week next to day-of-month 15. Classic cron ORs the two, so "0 0 15 * 1" would also run every Monday. Leave day-of-week as "*".
Assuming the server clock is your clock. Cron runs in the machine’s timezone unless the runtime says otherwise; the examples here are UTC.
No lock around a job that might overlap itself, and no alert when it silently stops. That second one is what Supercrontab is for.

Run it in your stack

Linux crontab Laravel WordPress Next.js / Vercel Node.js Python Docker GitHub Actions

// WP-Cron only fires on page loads. Disable it and call wp-cron.php
// from a real scheduler instead:
// define('DISABLE_WP_CRON', true);

0 0 15 * * curl -fsS https://example.com/wp-cron.php?doing_wp_cron

On low-traffic sites WP-Cron drifts. An external caller makes it exact.

Questions

Does 0 0 15 * * run in my local time?

Only if the scheduler is configured for it. crontab uses the system timezone; Vercel and GitHub Actions always use UTC; Laravel and node-cron take a timezone option. In Supercrontab the timezone is a field on the job.

What if the previous run is still going?

Classic cron starts the next run anyway. Add a lock (flock on Linux, withoutOverlapping() in Laravel) or let Supercrontab skip the tick while the previous request is open.

Is there a shorter way to write this?

No. The five-field form is the shortest portable version.