What is CRON_TZ?
A crontab directive that sets the timezone for schedule interpretation.
Definition
CRON_TZ is a variable used in crontab files and some cron services to specify which timezone should be used when interpreting schedule times. Setting CRON_TZ=America/New_York before a cron entry ensures that "0 9 * * *" means 9:00 AM Eastern, regardless of the server's system timezone. Not all cron implementations support CRON_TZ — it originated in Solaris and was adopted by some Linux distributions.
Simple Analogy
Like telling your assistant "when I say 9 AM, I mean 9 AM New York time" before giving them your schedule — it sets the context for interpreting all the times that follow.
Why It Matters
CRON_TZ solves the problem of scheduling jobs in different timezones on a single server. Without it, all cron jobs on a server run according to the system timezone, which may not match your business timezone. CronJobPro provides per-job timezone settings that work like CRON_TZ but with a user-friendly interface.
How to Verify
On Linux, check your crontab for a CRON_TZ line. Run `grep CRON_TZ /etc/crontab` or check user crontabs. In CronJobPro, the timezone is displayed on each job's configuration page. Verify by comparing execution timestamps with the expected local time.
Common Mistakes
Placing CRON_TZ after the cron entries instead of before them. Using a timezone name that the system does not recognize. Forgetting that CRON_TZ only affects cron scheduling, not the timezone of the commands being executed.
Best Practices
Set CRON_TZ per job or per block of related jobs. Use IANA timezone identifiers only. In managed services like CronJobPro, always explicitly set the timezone per job rather than relying on any default.
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What is CRON_TZ?
CRON_TZ is a variable used in crontab files and some cron services to specify which timezone should be used when interpreting schedule times. Setting CRON_TZ=America/New_York before a cron entry ensures that "0 9 * * *" means 9:00 AM Eastern, regardless of the server's system timezone. Not all cron implementations support CRON_TZ — it originated in Solaris and was adopted by some Linux distributions.
Why does CRON_TZ matter for cron jobs?
CRON_TZ solves the problem of scheduling jobs in different timezones on a single server. Without it, all cron jobs on a server run according to the system timezone, which may not match your business timezone. CronJobPro provides per-job timezone settings that work like CRON_TZ but with a user-friendly interface.
What are best practices for CRON_TZ?
Set CRON_TZ per job or per block of related jobs. Use IANA timezone identifiers only. In managed services like CronJobPro, always explicitly set the timezone per job rather than relying on any default.
Related Terms
Timezone
The regional time standard that determines when a scheduled job actually fires.
UTC (Coordinated Universal Time)
The global time standard with no daylight saving adjustments, used as the baseline for all timezones.
Daylight Saving Time (DST)
Seasonal clock adjustment that shifts local time by one hour, affecting cron job timing.
Crontab
The configuration file where cron jobs and their schedules are stored.