15th of the month
0 0 15 * *
At 00:00, on day 15 of the month. Midnight on the 15th, regardless of the weekday.
Check the next five runs
Output
The result shows up here. Your input is not written to the log.
Questions
›What does 0 0 15 * * mean?
At 00:00, on day 15 of the month
›Which timezone are the next runs in?
The expression is evaluated in UTC. This page also shows those times in the timezone of the browser you are using.