Cron monthly on the 1st at 18:00: the expression, explained, in Next.js / Vercel
The cron expression for “monthly on the 1st at 18:00” is 0 18 1 * *. This page shows what each field does, the next five times it will fire, the mistake most people make with it, and a working Next.js / Vercel example you can paste.
The expression
| Field | Value | Meaning |
|---|---|---|
| minute | 0 | exactly 0 |
| hour | 18 | exactly 18 |
| day of month | 1 | exactly 1 |
| month | * | every month |
| day of week | * | every day of week |
Next five runs (UTC, from now)
- 2026-10-01 18:00 UTC
- 2026-11-01 18:00 UTC
- 2026-12-01 18:00 UTC
- 2027-01-01 18:00 UTC
- 2027-02-01 18:00 UTC
Mistakes people make with this schedule
- Adding a day-of-week next to day-of-month 1. Classic cron ORs the two, so "0 18 1 * 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
// vercel.json
{
"crons": [
{ "path": "/api/cron/run", "schedule": "0 18 1 * *" }
]
}Vercel crons run in UTC and, on the Hobby plan, at most once a day. For anything more frequent call the route from Supercrontab.
Questions
Does 0 18 1 * * 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.