Seoul is 13 hours ahead of Philadelphia

There is no standard 8-to-6 overlap. Someone joins early or late.

The 13-hour difference means Philadelphia and Seoul miss each other entirely during regular office hours. Where you can, lean on async updates and save live calls for when one team is happy to start early or stay late. Daylight saving complicates things slightly: Philadelphia observes it, Seoul doesn't, so the difference flexes by an hour part of the year.