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Apache Airflow cron expression: every 12 hours
To run a Apache Airflow job every 12 hours, use:
0 0,12 * * *At minute 0, during hours 00, 12.
Your week at a glance
Upcoming runs
| # | Local | UTC | From now |
|---|
Copy-ready code
Why use this schedule
Twice a day, at midnight and noon. Written as a list, which is clearer than */12.
- Twice-daily database dumps
- Syncing a catalogue to a marketplace
- Morning and evening digest emails
First runs, as an example
Starting from 1 January 2027, evaluated in UTC:
| # | Date and time (UTC) |
|---|---|
| 1 | Fri, 01 Jan 2027, 00:00:00 |
| 2 | Fri, 01 Jan 2027, 12:00:00 |
| 3 | Sat, 02 Jan 2027, 00:00:00 |
| 4 | Sat, 02 Jan 2027, 12:00:00 |
| 5 | Sun, 03 Jan 2027, 00:00:00 |
| 6 | Sun, 03 Jan 2027, 12:00:00 |
Every 12 hours in every dialect
| System | Expression |
|---|---|
| Apache Airflow (this page) | 0 0,12 * * * |
| Quartz | 0 0 0,12 * * ? |
| Spring | 0 0 0,12 * * * |
| Crontab | 0 0,12 * * * |
| Kubernetes | 0 0,12 * * * |
| AWS EventBridge | 0 0,12 * * ? * |
| Jenkins | H 0,12 * * * |
| GitHub Actions | 0 0,12 * * * |
| node-cron | 0 0,12 * * * |
| Azure Functions | 0 0 0,12 * * * |
| Google Cloud Scheduler | 0 0,12 * * * |
Need to translate a different expression? Use the cron converter.
Ready-to-use Apache Airflow config
Drop this into your project. The expression is the one above.
from datetime import datetime
from airflow import DAG
from airflow.operators.empty import EmptyOperator
with DAG(
dag_id="my_dag",
start_date=datetime(2026, 1, 1),
schedule="0 0,12 * * *", # schedule_interval= before Airflow 2.4
catchup=False,
):
EmptyOperator(task_id="start")The Apache Airflow fields, in order: minute (0-59), hour (0-23), day-of-month (1-31), month (1-12), day-of-week (0-7, 0 and 7 = Sunday).
Things to watch out for in Apache Airflow
- A scheduled run starts after its data interval ends, so a daily 0 0 * * * run processes yesterday's interval just after midnight. Set catchup=False if you do not want backfills.
- Airflow defaults to UTC. On a time-zone-aware DAG a cron schedule follows wall-clock time, so a daily 00:00 US/Eastern run moves between 04:00 and 05:00 UTC across daylight saving changes.
The common mistake with this schedule
In UTC, midnight and noon fall at odd local times. For India, 00:00 and 12:00 UTC are 05:30 and 17:30 IST.
Frequently asked questions
How do I run a Apache Airflow job every 12 hours?
Use 0 0,12 * * *. At minute 0, during hours 00, 12.
What is the every 12 hours cron expression in other systems?
Quartz: 0 0 0,12 * * ?; Spring: 0 0 0,12 * * *; Crontab: 0 0,12 * * *. The table on this page lists every dialect.
Which time zone does Apache Airflow use for this schedule?
Airflow defaults to UTC. On a time-zone-aware DAG a cron schedule follows wall-clock time, so a daily 00:00 US/Eastern run moves between 04:00 and 05:00 UTC across daylight saving changes.