Cron · JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC
Month and weekday names
Cron accepts JAN–DEC and SUN–SAT, case-insensitively, but the numbering of Sunday differs between dialects.
Key facts
| Month names | JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC |
|---|---|
| Weekday names | SUN, MON, TUE, WED, THU, FRI, SAT |
| Case | Case-insensitive |
| Sunday | 0 and 7 both mean Sunday in Vixie cron |
| Monday | 1 in Vixie cron |
| Quartz | 1–7 with 1 = Sunday |
| Names in ranges | Allowed, e.g. MON-FRI |
Names make intent readable
0 9 * * MON-FRI is easier to audit than 0 9 * * 1-5, and both mean the same thing in Vixie-style cron. Names are not localized: they are always the three-letter English abbreviations, whatever the system language.
Mixing names and numbers inside one list is accepted by common implementations but is a portability risk. If a schedule will be read by another tool, prefer numbers and keep the mapping in a comment.
Sunday is the number that bites
In Vixie cron and cronie, day-of-week runs 0–7 with 0 and 7 both Sunday. In Quartz and Spring's six-field cron, 1 is Sunday and 7 is Saturday, so a job copied between the two dialects moves by one day — or fires on the wrong day entirely.
The safest habit is to write weekdays with names when the dialect supports them, and to run the expression through a parser for the target system before deploying it.
Frequently asked questions
Is 7 Sunday or Saturday in cron?
In Vixie cron, 7 is Sunday, the same as 0. Saturday is 6. In Quartz, 7 is Saturday.
Are cron names translated on non-English systems?
No. Month and weekday names are fixed English three-letter abbreviations.
Can I write MON-FRI?
Yes in Vixie-style implementations. Quartz uses different numbering, so verify before copying the expression.