Castro Valley to Seoul time converter

Seoul is 16 hours ahead of Castro Valley. When it is 9:00 AM in Castro Valley, it is 1:00 AM (Wed, Oct 21) in Seoul.

Castro Valley PDT

Tuesday, October 20, 2026

Seoul KST

Wednesday, October 21, 2026

Castro Valley
California, United States
Tue, Oct 20
PDTUTC-7
Seoul
South Korea
Wed, Oct 21
KSTUTC+9+16h
Finding your time zone…
Shared working hours (9:00–18:00)

Castro Valley to Seoul conversion table

Every hour of today in Castro Valley and the matching time in Seoul. Light rows are typical working hours (9:00–18:00).

Castro ValleySeoul
12:00 AM4:00 PM
1:00 AM5:00 PM
2:00 AM6:00 PM
3:00 AM7:00 PM
4:00 AM8:00 PM
5:00 AM9:00 PM
6:00 AM10:00 PM
7:00 AM11:00 PM
8:00 AM12:00 AM+1 day
9:00 AM1:00 AM+1 day
10:00 AM2:00 AM+1 day
11:00 AM3:00 AM+1 day
12:00 PM4:00 AM+1 day
1:00 PM5:00 AM+1 day
2:00 PM6:00 AM+1 day
3:00 PM7:00 AM+1 day
4:00 PM8:00 AM+1 day
5:00 PM9:00 AM+1 day
6:00 PM10:00 AM+1 day
7:00 PM11:00 AM+1 day
8:00 PM12:00 PM+1 day
9:00 PM1:00 PM+1 day
10:00 PM2:00 PM+1 day
11:00 PM3:00 PM+1 day

Best time to call or meet

Both sides are at work from 5:00 PM – 6:00 PM in Castro Valley (9:00 AM – 10:00 AM in Seoul).

Daylight saving time and the difference

The difference changes during the year because Castro Valley and Seoul switch clocks on different dates:

  • Oct 20, 2026 – Nov 1, 2026: +16h
  • Nov 1, 2026 – Mar 14, 2027: +17h
  • Mar 14, 2027 – Oct 20, 2027: +16h

Distance

Castro Valley and Seoul are 9,057 km (5,628 miles) apart in a straight line.

More conversions

Seoul to Castro ValleyCastro Valley to New YorkCastro Valley to LondonCastro Valley to Los AngelesCastro Valley to ChicagoCastro Valley to TorontoCastro Valley to São PauloCastro Valley to ParisCastro Valley to BerlinCastro Valley to MoscowCastro Valley to DubaiCastro Valley to New DelhiCastro Valley to Bangkok
New York to SeoulLondon to SeoulLos Angeles to SeoulChicago to SeoulToronto to SeoulSão Paulo to SeoulParis to SeoulBerlin to SeoulMoscow to SeoulDubai to SeoulNew Delhi to SeoulBangkok to Seoul

Questions and answers

What is the time difference between Castro Valley and Seoul?

Seoul is 16 hours ahead of Castro Valley.

What time is it in Seoul when it is 9 AM in Castro Valley?

When it is 9:00 AM in Castro Valley, it is 1:00 AM (Wed, Oct 21) in Seoul.

When is the best time to call Seoul from Castro Valley?

Both sides are at work from 5:00 PM – 6:00 PM in Castro Valley (9:00 AM – 10:00 AM in Seoul).

Does the time difference between Castro Valley and Seoul change?

Yes, for part of the year, because daylight saving time starts and ends on different dates or applies on one side only.