Update time zone when user travels I am creating a site that increments a "day" session at midnight. Is there a way to update the timezone set for that user when they travel between time zones?

Would using javascript to pull the value from the calendar on their computer be an option? Right now we are storing timezone values in the DB so this would be a major code change, but would it work? Is there any Drupal module that could help with this?
You can use javascript to get the browser timezone. Assuming their computer timezone is updated, their browser timezone will change.

var offset = new Date().getTimezoneOffset();


Or if you want the name you'll have to do something like https://stackoverflow.com/questions/2853474/can-i-get-the-browser-time-zone-in-asp-net-or-do-i-have-to-rely-on-js-operations

Sadly there is no way to do this without Javascript.