This KB article shows how to make a default selection for the Time Zone property or remove it from being a required field when editing a user.
To make a default selection for the 'time zone' user custom property:
- Go to Workarea > Settings > Configuration > Custom Properties to display the View User Custom Properties screen.
- Select the Time Zone property.
Inside the list here is a check box that says first option is not a valid selection. This will stop the default option of "select" from not being acceptable. - Uncheck the box.
- Scroll down the list of time zones and select the one you want to use as default and move it to the top of the list.