I have a cronjob which is executes every day at 9:00 AM of UTC-Time. I'm in GMT+1 so it executes at 10:00 AM local time. When there is the timezone change (to daylight saving time, DST), the cronjob executes still at 9:00 AM of UTC-Time but at 11:00 AM local time. But I want it always to execute at 10:00, no matter of summer time or not. How do I do that?


Check your setting in /etc/timezone. In the question you mentioned you are in "GMT+1", if that is what your timezone is set to, your script will always execute at UTC plus one hour. If you set it to e.g. "Europe/Paris", the time of execution will change with the daylight savings time.


This will likely depend on your OS and it's implementation of cron. This is not possible in the most popular cron implementation, vixie/isc cron. From the crontab(5) manpage:

       The  cron  daemon  runs with a defined timezone. It currently does not 
       support per-user timezones. All the tasks: system's and user's will 
       be run based on the configured timezone. Even if a user specifies  
       the TZ  environment  variable  in  his crontab this will affect only 
       the commands executed in the crontab, not the execution of the crontab 
       tasks themselves.

Expanding on @Cyrus answer this is what I did:

I made a script which checked a UTC offset:

export TZ=":US/Eastern"
if [ "$(date +%z)" == "$1" ]; then
  exec $@

Then I add two crontab entries each for the offset I want:

0 8 * * * run-only-with-tz.sh -0400 place_your_command_here
0 9 * * * run-only-with-tz.sh -0500 place_your_command_here

Move your cronjob to 8:00 and sleep one hour if you are in GMT+1

0 8 * * * [ "$(date +\%z)" = "+0100" ] && sleep 3600; place_your_command_here
  • What if your TZ is North America ? – swdev Mar 15 '19 at 8:04

From the manual page:

The daemon will use, if present, the definition from /etc/timezone for the timezone.

The environment can be redefined in user's crontab definitions but cron will only handle tasks in a single time‐ zone.

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