I'm wondering the same thing. The SquareSpace docs indicate that it's stuck on the local time of the publisher and doesn't automatically convert for a page visitor from a different time zone. "Start and end time. These are based on the time zone set in Language and Region Settings, and won't change based on a visitor's time zone."
If we're lucky, I'll assume that visitors can download a calendar invitation that may convert to local time. But for a general visitor, many events may look like they take place at a crazy time (for example, 3 a.m. Atlanta instead of 9 a.m. Paris).
I'm surprised that we can't either customize the time as we publish or the site can't ask for location services to automatically convert to visitors' local timezones.