scheduleTimezone

This term is proposed for full integration into Schema.org, pending implementation feedback and adoption from applications and websites.

Thing > Property > scheduleTimezone

Indicates the timezone for which the time(s) indicated in the Schedule are given. The value provided should be among those listed in the IANA Time Zone Database.
Values expected to be one of these types
Text
Used on these types
Schedule

Source

https://github.com/schemaorg/schemaorg/issues/1457