Run a Cron Job Every Other Hour
To run a job every other hour, use a step of 2 in the hour field: 0 */2 * * * runs at the top of every even hour (00:00, 02:00, 04:00, and so on). That is 12 times a day.
The expression
0 */2 * * * fires at minute 0 of every second hour: 00:00, 02:00, 04:00 … 22:00. The */2 step means 'every 2 hours' starting from 0.
Want the odd hours instead?
*/2 always starts at 0 (even hours). For odd hours (01:00, 03:00 …) list them: 0 1,3,5,7,9,11,13,15,17,19,21,23 * * *, or use a range with step 0 1-23/2 * * *.
Limit to a window
Every other hour during business hours only: 0 9-17/2 * * * runs at 9, 11, 13, 15, 17.
FAQ
What is the cron expression for every other hour?
0 */2 * * * runs at the top of every even hour (00:00, 02:00, …), 12 times a day.
How do I run on the odd hours instead?
*/2 starts at 0, so use a range with step: 0 1-23/2 * * * fires at 1, 3, 5 … 23.
Can I limit every-other-hour to work hours?
Yes. 0 9-17/2 * * * runs every other hour from 9 AM to 5 PM (9, 11, 13, 15, 17).