Reclaim automatically pulls your timezone from your Google Calendar Settings and uses it to schedule your events. To update or confirm what timezone Reclaim is using, go to your Google Calendar settings for the main account email that you use to login to Reclaim, and then go to Time zone under General.
If you're finding that Reclaim is scheduling your events at the wrong times or suspect that Reclaim has the wrong timezone, you may be experiencing a common bug with Google Calendar. Fix it by following the instructions in this doc.