Cron expression for daily at midnight

The cron expression 0 0 * * * runs a job at midnight every day — exactly when the wall clock reads 00:00. Standard 5-field syntax works in Linux crontab, Kubernetes CronJob and GitHub Actions; AWS EventBridge needs the 6-field form cron(0 0 * * ? *). The single biggest gotcha: most schedulers default to UTC, not your local timezone.

Quick reference

Which timezone is “midnight”?

This is the question that catches everyone at least once. The cron expression 0 0 * * * is a wall-clock pattern: fire when the displayed minute is 0 and the displayed hour is 0. But which clock?

Each platform has a default:

• Linux crontab uses the system’s /etc/localtime — usually whatever you set when installing the OS. Run date on the host to see what cron sees.
• Kubernetes < 1.25 uses the kube-controller-manager pod’s local time. On managed Kubernetes (EKS, GKE, AKS) this is UTC. Self-hosted clusters can be anything.
• Kubernetes ≥ 1.25 accepts a spec.timeZone field. If unset, falls back to controller local. Always set it explicitly.
• GitHub Actions is hardcoded UTC. There is no override; you must convert.
• AWS EventBridge Rules is hardcoded UTC. EventBridge Scheduler (newer service) accepts ScheduleExpressionTimezone.

If you wrote 0 0 * * * thinking “midnight in my timezone” and the scheduler is on UTC, your job runs at 4 PM the previous day for someone on the US West Coast. The fix is either to convert your time to UTC, or to set the timezone explicitly.

Variations

How do I use it on each platform?

Linux crontab:

0 0 * * * /usr/local/bin/nightly-cleanup

Or with the shortcut:

@daily /usr/local/bin/nightly-cleanup

Kubernetes CronJob (1.25+ with explicit timezone):

apiVersion: batch/v1
kind: CronJob
metadata:
  name: nightly-cleanup
spec:
  schedule: "0 0 * * *"
  timeZone: "America/Los_Angeles"     # critical — runs at local midnight
  successfulJobsHistoryLimit: 3
  jobTemplate:
    spec:
      template:
        spec:
          containers:
            - name: cleanup
              image: my-org/cleanup:1.0
          restartPolicy: OnFailure

AWS EventBridge Scheduler (with timezone):

Type: AWS::Scheduler::Schedule
Properties:
  Name: nightly-cleanup
  ScheduleExpression: 'cron(0 0 * * ? *)'
  ScheduleExpressionTimezone: 'America/Los_Angeles'
  FlexibleTimeWindow:
    Mode: 'OFF'
  Target:
    Arn: !GetAtt CleanupFunction.Arn
    RoleArn: !GetAtt SchedulerRole.Arn

GitHub Actions (UTC only):

on:
  schedule:
    - cron: '0 0 * * *'      # this is midnight UTC, not your local midnight

Common mistakes

Assuming 0 0 * * * runs at your midnight. It runs at the scheduler’s midnight. Always set the timezone explicitly when the platform supports it; otherwise convert to UTC.

Daylight saving silently shifts the run. A timezone like America/Los_Angeles follows DST. A job set to “midnight Pacific” is at 08:00 UTC half the year and 07:00 UTC the other half. If your downstream system expects a fixed UTC time, use UTC directly instead of a timezone.

Confusing 0 0 * * * with * * * * * or other typos. 0 0 * * * is daily; * * * * * is every minute (1440 runs/day). Easy to mis-type when copying.

The timezone story is the biggest gotcha here — for the full set of platform-specific knobs (Kubernetes timeZone post-1.25, EventBridge Scheduler ScheduleExpressionTimezone), see the Kubernetes CronJob schedule generator and the AWS EventBridge cron generator.

For other schedules see common cron schedules, or build a custom expression with the Cron Expression Builder.