While adding new or updating old members, you can add time zones. To do this, go to Members → Import Members. In the excel, make a column with the time zones for your members.
Here is a list of all time zones you can add to the excel before importing:
When you upload the excel, select the time zone Column and proceed to upload.
Once you have uploaded, you will be able to preview the information being uploaded.
After uploading the excel, you can view the members and the relevant time zones on the Members Listing page.