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Cron Every Hour: 0 * * * *

The cron expression for every hour is 0 * * * *. It runs 24 times per day, and the table below explains every field.

  • Cron expression
    0 * * * *
  • Schedule
    every hour
  • Runs per day
    24
  • Runs per 30 days
    720
  • systemd OnCalendar
    hourly
  • AWS EventBridge
    cron(0 * * * ? *)

What 0 * * * * means

FieldValueMeaning
Minute0at minute 0
Hour*every hour
Day of month*every day
Month*every month
Day of week*every day of the week

The five fields of a standard cron expression are, in order: minute, hour, day of month, month and day of week.

When every hour runs

The first run times in a day are: 00:00, 01:00, 02:00, 03:00, 04:00, 05:00, 06:00, 07:00, 08:00, 09:00, 10:00, 11:00, .... Over time that is 24 per day, 168 per week, about 720 per 30 days and 8,760 per year.

Copy-ready syntax for every hour

crontab

0 * * * * /path/to/script.sh >> /var/log/job.log 2>&1

GitHub Actions

on:
  schedule:
    - cron: '0 * * * *'

GitHub Actions runs scheduled workflows in UTC and may start them a few minutes late when GitHub is busy.

Kubernetes CronJob

apiVersion: batch/v1
kind: CronJob
spec:
  schedule: "0 * * * *"
  concurrencyPolicy: Forbid

Setting concurrencyPolicy: Forbid stops a new run from starting while the previous one is still going.

systemd timer

[Timer]
OnCalendar=hourly
Persistent=true

AWS EventBridge

cron(0 * * * ? *)

EventBridge cron has six fields and needs a ? in either the day-of-month or the day-of-week field. The simpler rate(1 hour) form works for fixed intervals.

When to use every hour

Web application firewalls update their blocklists hourly to incorporate newly identified malicious IP addresses. Usage metering services also tally resource consumption at the top of each hour to enforce billing quotas accurately.

What can go wrong

When dozens of hourly jobs share the zero minute mark, the resulting CPU spike can delay critical processes. Staggering start times manually is required to prevent this predictable congestion from degrading overall system responsiveness.

Cron uses the time zone of the machine or service running it, so check whether that is UTC or local time before you rely on the clock times above.

Other common schedules

FAQ

What is the cron expression for every hour?

Use 0 * * * *. It is the standard five-field form accepted by Linux crontab, Kubernetes CronJobs and GitHub Actions.

How many times a day does 0 * * * * run?

24 times per day, or 720 over 30 days.

How do I test a cron expression?

Build it in the cron builder, which explains each field in plain English and lists the next run times.

More cron