Path: Personal Settings >> Profile Information >> Selecting Your Timezone
The timezone option appears first while registering for a community. It helps us to select a timezone of our choice. By default, the timezone is America/ Los_Angeles. To edit the timezone you could simply change it from the Personal Settings section.
Any export or import done by the administrator of the community will allow them to select a timezone of their wish. However, any automated email or notifications triggered due to any idea or comment submitted in the community or broadcast emails or any other kind of scheduled emails will not be as per the timezone selected.
In terms of a normal user, it is an option that they can select from the Personal Settings section.
Please look out for more updates in the near future.