Offset
The time difference between Seoul and Mountain Time is 15 hours.
Seoul (KST) is ahead of Mountain Time (MDT).
KST: UTC+9
MDT: UTC-6
Mountain Time is currently observing daylight saving time; Seoul is not.
When to schedule
Standard business hours (9 AM–5 PM, Mon–Fri) in Seoul and Mountain Time don't overlap on the same weekday. Mountain Time is 15 hours behind Seoul.
Realistic options: hand off asynchronously, or stretch one side by an hour to catch the other team at the start or end of their day.
This window may shift by an hour during daylight saving time.
Public holidays in 2026
National public holidays can affect availability — a counterpart is likely off work on their own holidays, so it's worth planning meetings and deadlines around them.
South Korea
- New Year's DayThu, Jan 1
- Lunar New YearMon, Feb 16
- Lunar New YearTue, Feb 17
- Lunar New YearWed, Feb 18
- Independence Movement DayMon, Mar 2
- Labour DayFri, May 1
- Children's DayTue, May 5
- Buddha's BirthdayMon, May 25
- Local Election DayWed, Jun 3
- Memorial DaySat, Jun 6
- Constitution DayFri, Jul 17
- Liberation DayMon, Aug 17
- ChuseokThu, Sep 24
- ChuseokFri, Sep 25
- ChuseokSat, Sep 26
- National Foundation DayMon, Oct 5
- Hangul DayFri, Oct 9
- Christmas DayFri, Dec 25
United States
- New Year's DayThu, Jan 1
- Martin Luther King, Jr. DayMon, Jan 19
- Presidents DayMon, Feb 16
- Memorial DayMon, May 25
- Juneteenth National Independence DayFri, Jun 19
- Independence DayFri, Jul 3
- Labour DayMon, Sep 7
- Columbus DayMon, Oct 12
- Veterans DayWed, Nov 11
- Thanksgiving DayThu, Nov 26
- Christmas DayFri, Dec 25
About these zones
Seoul uses Korea Standard Time (KST). To call South Korea, dial +82.
Mountain Time is also known as MST, or MDT. To call United States, dial +1.
Mountain Time is approximately 6,150 miles northeast of Seoul.
Quick reference
Full 24-hour conversion table — tap any time to open it in the converter.
| Seoul | MST | Day |
|---|---|---|
| 12:00 am | 9:00 am | -1 day |
| 1:00 am | 10:00 am | -1 day |
| 2:00 am | 11:00 am | -1 day |
| 3:00 am | 12:00 pm | -1 day |
| 4:00 am | 1:00 pm | -1 day |
| 5:00 am | 2:00 pm | -1 day |
| 6:00 am | 3:00 pm | -1 day |
| 7:00 am | 4:00 pm | -1 day |
| 8:00 am | 5:00 pm | -1 day |
| 9:00 am | 6:00 pm | -1 day |
| 10:00 am | 7:00 pm | -1 day |
| 11:00 am | 8:00 pm | -1 day |
| 12:00 pm | 9:00 pm | -1 day |
| 1:00 pm | 10:00 pm | -1 day |
| 2:00 pm | 11:00 pm | -1 day |
| 3:00 pm | 12:00 am | Same day |
| 4:00 pm | 1:00 am | Same day |
| 5:00 pm | 2:00 am | Same day |
| 6:00 pm | 3:00 am | Same day |
| 7:00 pm | 4:00 am | Same day |
| 8:00 pm | 5:00 am | Same day |
| 9:00 pm | 6:00 am | Same day |
| 10:00 pm | 7:00 am | Same day |
| 11:00 pm | 8:00 am | Same day |
Daylight saving time
Mountain Time observes daylight saving time; Seoul does not. The offset between the two zones changes when Mountain Time transitions: on Sunday, November 1, 2026, clocks fall back from MDT to MST.
See the daylight saving time page for transition dates across every time zone.
Daylight today
- Sunrise
- 5:11 AM
- Sunset
- 7:53 PM
- Day length
- 14h 42m
- Sunrise
- 5:33 AM
- Sunset
- 8:28 PM
- Day length
- 14h 56m
Cities in these zones
Cities in Mountain Time
Browse all cities to see the current local time anywhere.
Airports in these zones
Airports in Korea Standard Time
- GMP
- ICN
- PUS
- TAE
- CJJ
- KWJ
- MWX
Airports in Mountain Time
- BJC
- DEN
- OGD
- SLC
Related conversions
Common conversions
- What is 9:00 am Seoul in MST?
- 9:00 am Seoul is 6:00 pm MST, the previous day.
- What is 12:00 pm Seoul in MST?
- 12:00 pm Seoul is 9:00 pm MST, the previous day.
- What is 12:30 pm Seoul in MST?
- 12:30 pm Seoul is 9:30 pm MST, the previous day.
- What is 2:00 pm Seoul in MST?
- 2:00 pm Seoul is 11:00 pm MST, the previous day.
- What is 5:00 pm Seoul in MST?
- 5:00 pm Seoul is 2:00 am MST.
- What is 11:30 pm Seoul in MST?
- 11:30 pm Seoul is 8:30 am MST.