Jenkins version is 2.235.5 (I should update it to next LTS version 2.249).

I configured Jenkins to run a job periodically every 30 days: Build Triggers → Build periodically → Schedule:

```
H 3 */30 * *
```

And now I see:

> Would last have run at Saturday, October 31, 2020 3:20:39 AM EDT; would next run at Sunday, November 1, 2020 3:20:39 AM EST.


[![Jenkins Build Triggers → Build periodically → Schedule][1]][1]

So it will be started again after 1 day, not 30 days…

How to run a job periodically every 30 days?

Update: history of Jenkins "predictions" for schedule above (job was created October 28):

> Would last have run at Thursday, October 1, 2020 3:20:06 AM EDT; would next run at Saturday, October 31, 2020 3:20:06 AM EDT.

> Would last have run at Saturday, October 31, 2020 3:20:39 AM EDT; would next run at Sunday, November 1, 2020 3:20:39 AM EST.

> Would last have run at Sunday, November 1, 2020 3:20:43 AM EST; would next run at Tuesday, December 1, 2020 3:20:43 AM EST.



  [1]: https://i.sstatic.net/fzC5U.png