Cron DST Check

Cron expressions are explained everywhere; what bites in production is the time zone. Paste a 5-field cron expression and pick a zone to see which upcoming runs fall on a wall-clock time that daylight saving time deletes (spring forward) or repeats (fall back).

Cron expression (minute hour day-of-month month day-of-week) IANA time zone

How to read this

SKIPPED — that local time does not exist on that date (the clock jumps over it). Whether your scheduler runs the job late, early, or not at all depends on the scheduler.
REPEATED — that local time happens twice (the clock goes back). Some schedulers run the job twice.
The portable fix is to schedule in UTC, or to avoid wall-clock times in the zone's transition hour (commonly 01:00–03:00).

Limits. This tool lists when a wall-clock time exists in the zone; it does not emulate any particular scheduler. Vixie cron, systemd timers, Kubernetes CronJob, and cloud schedulers handle DST differently, so check your scheduler's documentation for what it does with a skipped or repeated time. Only standard 5-field syntax is supported (*, lists, ranges, steps, month/day names; no L, W, #, @ aliases or seconds). When day-of-month and day-of-week are both restricted, a day matches if either does (Vixie behavior); some schedulers use AND. Zone data comes from your browser's own time zone database. Everything runs locally; nothing is sent anywhere.