How cron works
A cron expression has five fields: minute (0 to 59), hour (0 to 23), day of the month (1 to 31), month (1 to 12 or jan to dec) and day of the week (0 to 6 or sun to sat, where 0 and 7 are Sunday). A star means every value.
Special characters
A comma lists values, like 1,15. A dash makes a range, like 1-5 for Monday to Friday. A slash sets a step, like */10 for every 10 minutes. Shortcuts such as @daily, @hourly and @weekly work too.
Day of month and day of week
When both day fields are set, standard cron runs on days that match either one, not both. For example 0 9 1 * mon runs on the 1st of every month and on every Monday.
Time zones
Next run times are shown in this device's time zone. Servers often run cron in UTC, so check your server's setting before you rely on a schedule.