Cron explainer
Describe a five-field cron expression and list the next five local run times.

Details
Paste five cron fields and read what they mean, plus the next five times they would run on this device's clock. The fields are minute, hour, day of month, month, and weekday. Names such as MON are not accepted. Both day fields must match.

Category: Developer
Page: /tools/cron-explainer
Text: /tools/cron-explainer.txt

Limits
Five fields only: minute, hour, day of month, month, weekday. Names like MON are not accepted. Both day fields must match.

Steps
1. Type an expression such as */15 * * * *.
2. Read the field summary.
3. Check the next five times in your timezone.

Questions
Why might next times be empty?
A day-of-month that never lands in the allowed months returns an error.

Does Sunday have two numbers?
Use 0 for Sunday. 7 is rejected.

Is this Quartz?
No. Quartz seconds and the extra year field are not supported.