Cron Job on the Last Day of the Month

Closest cron expression

55 23 28-31 * *

At 23:55, between day 28 and 31 of the month. On its own, it runs on 41 days a year.

Standard cron has no “last day” symbol. Quartz’s L isn’t supported by crontab, Kubernetes or GitHub Actions. The usual fix is to schedule the job on every day that could be the last one, the 28th to the 31st, and let the command check whether tomorrow is the 1st.

Workaround: run a job on the last day of the month

This uses GNU date (Linux). On macOS or BSD, replace date -d tomorrow with date -v+1d.

55 23 28-31 * * [ "$(date -d tomorrow +\%d)" = "01" ] && /usr/local/bin/job.sh

The same idea works on every scheduler below: keep the base schedule and put the check at the start of the job’s command or script.

Field by field

Examples

crontab

Run crontab -e and add:

55 23 28-31 * * /usr/local/bin/job.sh >> /var/log/job.log 2>&1

For the exact schedule, use the workaround line above instead.

Kubernetes CronJob

apiVersion: batch/v1
kind: CronJob
metadata:
  name: my-job
spec:
  schedule: "55 23 28-31 * *"
  timeZone: "Etc/UTC"          # Kubernetes 1.27+
  concurrencyPolicy: Forbid    # skip a run if the last one is still going
  jobTemplate:
    spec:
      template:
        spec:
          containers:
            - name: job
              image: ghcr.io/acme/job:1.0
          restartPolicy: OnFailure

GitHub Actions

on:
  schedule:
    - cron: '55 23 28-31 * *'   # UTC

GitHub evaluates schedules in UTC, and runs can start several minutes late at busy times.

systemd timer

# /etc/systemd/system/job.timer
[Unit]
Description=Run job.service on the last day of the month

[Timer]
OnCalendar=*-*-28..31 23:55:00
Persistent=true

[Install]
WantedBy=timers.target

Enable it with systemctl enable --now job.timer, and check the next runs with systemd-analyze calendar "*-*-28..31 23:55:00". Persistent=true runs a missed job after downtime, which cron can’t do.

AWS EventBridge

cron(55 23 28-31 * ? *)

EventBridge cron has six fields (the last is the year), uses ? in either the day-of-month or the day-of-week field, and numbers weekdays from 1 (Sunday) to 7. Rules run in UTC; EventBridge Scheduler also accepts a time zone.

Similar schedules: monthly and yearly

• Every month: 0 0 1 * *
• On the 15th of every month: 0 0 15 * *
• Twice a month: 0 0 1,15 * *
• On the first Monday of the month: 0 9 1-7 * *
• Every quarter: 0 0 1 */3 *
• Every 6 months: 0 0 1 */6 *
• Every year: 0 0 1 1 *

Have a different schedule? Paste any expression into the Cron Expression Generator, or browse all cron examples.

Sources

• POSIX: crontab
• crontab(5) manual page
• Kubernetes docs: CronJob
• GitHub Actions docs: schedule event
• systemd.time(7): calendar events
• AWS docs: EventBridge Scheduler cron expressions

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Frequently asked questions