How does the set time zone affect reports?

Email reports and in-app metrics will always be displayed from the perspective of each inbox’s set time zone. If you are viewing metrics for an inbox in a different time zone, their metrics will display from the perspective of their set time zone (not yours).

If you prefer to see metrics for out-of-timezone inboxes from the perspective of your own time zone, then you can set the time zone of the inboxes to your own time zone.