Seoul is 14 hours ahead of Washington DC during Eastern Standard Time (or 13 hours during EDT). Washington DC uses Eastern Time (ET, UTC-5/-4) while Seoul uses Korea Standard Time (KST, UTC+9). When it's 12:00 PM in Washington DC, it's 2:00 AM the next day in Seoul.
Washington DC observes daylight saving time while South Korea does not. This means the difference varies between 13 and 14 hours throughout the year.
Best calling time: 6:00 PM - 9:00 PM Washington DC time. This corresponds to 8:00 AM - 11:00 AM in Seoul (during EST), catching morning business hours in South Korea.
Washington DC and Seoul have critical diplomatic and security ties. The US has major military presence in South Korea, and constant communication between the two capitals is essential for security and economic matters on the Korean Peninsula.