Note that this is going to be an expensive operation for CVS, as every polling requires Jenkins to scan the entire workspace and verify it with the server. Consider setting up a "push" trigger to avoid this overhead, as described in this document
The schedule is evaluated in the time zone of the Jenkins controller by
default. To use a different time zone, specify it on the first line of the
schedule field using
TZ=
followed by a time zone ID, for example:
TZ=Europe/London H/15 * * * *
See the help for the "Build periodically" trigger for the full schedule syntax and the list of supported time zone IDs.