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South Korea — Sea Water Temperature and Annual Ranges

Up-to-date sea water temperatures for the coasts of South Korea. Learn about today’s conditions, monthly averages, and how the surrounding seas and oceans vary by season. We find every place where you can swim and show you the water temperature there today and throughout the year.

South Korea
South Korea © Marcella Astrid, CC BY-SA 3.0

Sea Water Temperature Along the Coast

18.5°C
minimum
20.8°C
average
23.3°C
maximum
Get instant access to real-time water temperatures for this and all other locations with our iOS and Android apps.

Chart of Average Temperature Changes Over the Last 60 Days

From April 15 to June 15

Places with the Warmest Sea Water Today

23°C
Yeosu
23°C
Yeosu Strait
22°C
Tongyeong
22°C
Jeju Island
22°C
Masan
22°C
Geoje
21°C
Busan
21°C
Hwaseong
21°C
Ulsan
21°C
Gunsan
21°C
Boryeong
20°C
Incheon

The Most Popular Seaside Places

Coastal Seas and Oceans

Water Temperature and Swimming Overview

Regions and Map

Water Temperature Trends

South Korea is a peninsular country with a varied coastline along the Yellow Sea to the west, the East Sea (Sea of Japan) to the east, and the Korea Strait to the south, including warmer waters around Jeju Island. Sea surface temperatures vary by region and season. In winter, coastal waters commonly drop to about 2–10 °C (36–50 °F), with the coldest values in the north and somewhat milder conditions in the far south. Spring brings a steady rise to roughly 8–18 °C (46–64 °F). Peak summer temperatures are typically between 20–28 °C (68–82 °F), with southern shores and Jeju often at the warmest end of that range. Autumn temperatures cool from summer highs to a range around 15–22 °C (59–72 °F) before winter sets in.

Swimming Conditions

Swimming is widely permitted and popular during the warm season, particularly from June through early September when many beaches are staffed by lifeguards and facilities are open. Outside these months the water is generally too cold for comfortable recreational swimming without a wetsuit and presents risks such as cold-water shock and hypothermia. Even in summer swimmers should heed warnings about strong currents, sudden weather changes, and occasional jellyfish or algal blooms. Surfing and cold-water swimming communities remain active year-round with appropriate gear and caution. Local authorities post advisories and close beaches during typhoons or hazardous conditions, so checking local guidance is advisable before entering the water.