Cron: daily at 3 AM
The cron expression `0 3 * * *` fires once a day at 03:00. Classic nightly-batch window. What goes wrong with DST and how to avoid it.
# expression
0 3 * * * Means: At minute 0 of hour 3, every day — once a day at 03:00 sharp.
→ Open in cron builder (pre-filled)
# common use cases
- Nightly database backups during the off-peak window.
- Log rotation, anti-spam recomputation, end-of-day reports.
- Cache warmups before the morning traffic peak.
# next fires (sample)
Day 1 03:00Day 2 03:00Day 3 03:00Day 4 03:00Day 5 03:00
# pitfalls
- On the spring-forward DST day, 02:00 → 03:00 instantly. The 03:00 fire may be skipped or fire at 04:00 depending on runner. Schedule in UTC to avoid.
- If multiple nightly jobs run at 03:00 they pile up. Stagger: one at 03:00, next at 03:15, etc.