Cron DST Transition Preview

Inspect your schedule near upcoming daylight-saving transitions. This preview shows CronWizard's parser behavior; it does not simulate every target runtime. Cron syntax alone does not define what a scheduler does when an hour disappears or occurs twice.

Clock moves backward

Sunday, November 1, 2026 at 1:00 AM

UTC-04:00 → UTC-05:00

A range of local wall-clock times occurs twice during this transition. A job inside the repeated range may execute twice, depending on the scheduler.

Local clock boundary

Nov 1, 2026, 1:59:59 AM EDT → Nov 1, 2026, 1:00:00 AM EST

CronWizard parser preview from one minute before the boundary

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This list reflects the cron-parser policy used by CronWizard. Kubernetes, Cronie, Spring, GitHub Actions, and other runtimes can skip, shift, deduplicate, or repeat ambiguous local times differently. Confirm the exact target's documented behavior before deployment.

Clock moves forward

Sunday, March 14, 2027 at 3:00 AM

UTC-05:00 → UTC-04:00

A range of local wall-clock times does not exist during this transition. A job scheduled inside the skipped range may run later or be skipped, depending on the scheduler.

Local clock boundary

Mar 14, 2027, 1:59:59 AM EST → Mar 14, 2027, 3:00:00 AM EDT

CronWizard parser preview from one minute before the boundary

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This list reflects the cron-parser policy used by CronWizard. Kubernetes, Cronie, Spring, GitHub Actions, and other runtimes can skip, shift, deduplicate, or repeat ambiguous local times differently. Confirm the exact target's documented behavior before deployment.

Clock moves backward

Sunday, November 7, 2027 at 1:00 AM

UTC-04:00 → UTC-05:00

A range of local wall-clock times occurs twice during this transition. A job inside the repeated range may execute twice, depending on the scheduler.

Local clock boundary

Nov 7, 2027, 1:59:59 AM EDT → Nov 7, 2027, 1:00:00 AM EST

CronWizard parser preview from one minute before the boundary

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  3. 3.
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This list reflects the cron-parser policy used by CronWizard. Kubernetes, Cronie, Spring, GitHub Actions, and other runtimes can skip, shift, deduplicate, or repeat ambiguous local times differently. Confirm the exact target's documented behavior before deployment.

Why DST can break an otherwise valid cron schedule

During a spring-forward transition, clocks skip a block of local times. During a fall-back transition, a block of local times repeats. Whether a cron job is skipped, delayed, or executed twice is a runtime policy of the target scheduler—not something encoded in the five cron fields.

For critical workloads, prefer UTC or make the job idempotent and protect it with a distributed lock. Review the target platform documentation and test the exact runtime behavior before deployment. See the cron production best-practices guide and troubleshooting guide for operational safeguards.