FAQ: How are timezones handled when sharing queries with people in different timezones?

The browser sends its timezone to the server and that determines the cutoff. Timezones are not embedded in the URL - if a query is shared across timezones, the day cutoff will differ. The bucket() and timeChart() functions lets you specify an explicit timezone (i.e., timechart(..., timezone=Z)). This will overrule the timezone of the browser.