Question 1

What happens if I set both day-of-month and day-of-week?

Accepted Answer

Cron treats them as OR, not AND: the job runs if either matches. People who think they wrote the 1st and on Mondays have actually written the 1st or every Monday.

Question 2

Which timezone applies?

Accepted Answer

The next-run times here use your browser's local time. Cron on a server uses the system timezone, which is typically UTC, and can behave differently across daylight saving transitions.

Cron Expression Explainer