INSTRUMENT / SEA TEMPERATURE
Jeju Island Water Temperature
Updated Sun 16:00 (Asia/Seoul)
South Korea · Forecast updated Nov 8, 2026, 16:00 UTC
Current Sea Temperature
23.1°C
73.6°F
Mild water
Valid Nov 8, 2026, 16:00 (Asia/Seoul). Source: stored Open-Meteo marine forecast. Temperature is not a safety rating or snorkel score.
Versus this month's average
0.3°C above
The typical November average is 22.8°C (73.0°F) from the historical baseline.
Recent trend
Cooling by 0.7°C
Seven-day average: 23.8°C, versus 24.5°C in the prior seven days.
What to wear
Mild water
A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Cold tolerance varies. Wind, session length, sunshine, and exertion also affect comfort; temperature alone does not describe sea conditions or replace the snorkel forecast.
Typical Sea Temperature Over the Year
In the historical baseline for Jeju Island, typical monthly averages range from about 15.5°C (59.9°F) in March to 30.0°C (86.0°F) in August.
Over the past 30 days, the average sea temperature in Jeju Island has been 24.8°C.
Historical baseline (full year)
Northern Hemisphere. Summer is generally June–August; winter is December–February.
Typical monthly sea-surface temperature near Jeju Island, calculated from hourly observations for 2023–2025. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 16.2–17.1°C | 16.7°C / 62.1°F |
| February | 15.7–16.2°C | 16.0°C / 60.8°F |
| March | 14.1–16.4°C | 15.5°C / 59.9°F |
| April | 15.0–17.4°C | 16.4°C / 61.5°F |
| May | 17.0–18.8°C | 18.2°C / 64.8°F |
| June | 21.7–22.4°C | 22.1°C / 71.8°F |
| July | 26.1–27.9°C | 26.7°C / 80.1°F |
| August | 29.5–30.9°C | 30.0°C / 86.0°F |
| September | 28.1–29.9°C | 29.2°C / 84.6°F |
| October | 24.7–27.6°C | 26.1°C / 79.0°F |
| November | 22.2–23.1°C | 22.8°C / 73.0°F |
| December | 19.2–19.5°C | 19.3°C / 66.7°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Nearest sea grid cell (33.21, 126.54). Each month is the mean of yearly monthly means; the range is the lowest and highest of those yearly monthly means. Open-Meteo methodology.
Water temperature by month
Each month uses the 2023–2025 baseline. The range is the lowest and highest yearly monthly mean, not an hourly extreme.
Jeju Island in January
Typical January water temperature near Jeju Island is 16.7°C (62.1°F), with yearly monthly means from 16.2–17.1°C.
Swimming and snorkeling: cold water. Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.
Adjacent months: December 19.3°C · February 16.0°C.
Explore Jeju Island sea temperature in January, including swim comfort and month comparisons →
Jeju Island in February
Typical February water temperature near Jeju Island is 16.0°C (60.8°F), with yearly monthly means from 15.7–16.2°C.
Swimming and snorkeling: cold water. Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.
Adjacent months: January 16.7°C · March 15.5°C.
Explore Jeju Island sea temperature in February, including swim comfort and month comparisons →
Jeju Island in March
Typical March water temperature near Jeju Island is 15.5°C (59.9°F), with yearly monthly means from 14.1–16.4°C.
Swimming and snorkeling: cold water. Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.
Adjacent months: February 16.0°C · April 16.4°C.
Explore Jeju Island sea temperature in March, including swim comfort and month comparisons →
Jeju Island in April
Typical April water temperature near Jeju Island is 16.4°C (61.5°F), with yearly monthly means from 15.0–17.4°C.
Swimming and snorkeling: cold water. Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.
Adjacent months: March 15.5°C · May 18.2°C.
Explore Jeju Island sea temperature in April, including swim comfort and month comparisons →
Jeju Island in May
Typical May water temperature near Jeju Island is 18.2°C (64.8°F), with yearly monthly means from 17.0–18.8°C.
Swimming and snorkeling: cool water. A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Adjacent months: April 16.4°C · June 22.1°C.
Explore Jeju Island sea temperature in May, including swim comfort and month comparisons →
Jeju Island in June
Typical June water temperature near Jeju Island is 22.1°C (71.8°F), with yearly monthly means from 21.7–22.4°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: May 18.2°C · July 26.7°C.
Explore Jeju Island sea temperature in June, including swim comfort and month comparisons →
Jeju Island in July
Typical July water temperature near Jeju Island is 26.7°C (80.1°F), with yearly monthly means from 26.1–27.9°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: June 22.1°C · August 30.0°C.
Explore Jeju Island sea temperature in July, including swim comfort and month comparisons →
Jeju Island in August
Typical August water temperature near Jeju Island is 30.0°C (86.0°F), with yearly monthly means from 29.5–30.9°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: July 26.7°C · September 29.2°C.
Explore Jeju Island sea temperature in August, including swim comfort and month comparisons →
Jeju Island in September
Typical September water temperature near Jeju Island is 29.2°C (84.6°F), with yearly monthly means from 28.1–29.9°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: August 30.0°C · October 26.1°C.
Explore Jeju Island sea temperature in September, including swim comfort and month comparisons →
Jeju Island in October
Typical October water temperature near Jeju Island is 26.1°C (79.0°F), with yearly monthly means from 24.7–27.6°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: September 29.2°C · November 22.8°C.
Explore Jeju Island sea temperature in October, including swim comfort and month comparisons →
Jeju Island in November
Typical November water temperature near Jeju Island is 22.8°C (73.0°F), with yearly monthly means from 22.2–23.1°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: October 26.1°C · December 19.3°C.
Explore Jeju Island sea temperature in November, including swim comfort and month comparisons →
Jeju Island in December
Typical December water temperature near Jeju Island is 19.3°C (66.7°F), with yearly monthly means from 19.2–19.5°C.
Swimming and snorkeling: cool water. A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Adjacent months: November 22.8°C · January 16.7°C.
Explore Jeju Island sea temperature in December, including swim comfort and month comparisons →
Forecast archive (growing)
These values come from hourly forecasts SnorkelForecast has stored. They cover only months with records and do not replace the historical baseline.
| Month | Min | Average | Max |
|---|---|---|---|
| June | 22.2°C / 72.0°F | 23.0°C / 73.4°F | 24.6°C / 76.3°F |
| July | 23.4°C / 74.1°F | 26.7°C / 80.0°F | 30.9°C / 87.6°F |
| August | 27.8°C / 82.0°F | 28.9°C / 84.1°F | 30.5°C / 86.9°F |
| September | 26.5°C / 79.7°F | 27.6°C / 81.6°F | 29.8°C / 85.6°F |
| October | 24.2°C / 75.6°F | 25.5°C / 77.9°F | 27.3°C / 81.1°F |
| November | 22.9°C / 73.2°F | 23.6°C / 74.5°F | 24.2°C / 75.6°F |
Partial coverage: 6 calendar months with records. Profile calculated from 3865 hourly forecast records across 6 monthly periods. This is a growing archive, not a long-term climate normal.
About the water at Jeju Island
Volcanic island with clear coves, lava arches and the famous haenyeo divers.
- Area
- Jeju
Jeju Island Water Temperature: Common Questions
What is the water temperature in Jeju Island today?
The current sea surface temperature near Jeju Island is 23.1°C (73.6°F). Over the last 30 days, the average has been 24.8°C.
When is the water warmest in Jeju Island?
The water is typically warmest in August, at around 30.0°C (86.0°F) in the 2023–2025 historical baseline.
When is the water coldest in Jeju Island?
The water is typically coldest in March, at around 15.5°C (59.9°F) in the same historical baseline. A wetsuit is usually recommended during this period.
Can you swim in Jeju Island today?
At 23.1°C, the water is usually comfortable for swimming and snorkeling.
Full Snorkeling Forecast
See how today's sea temperature, wave height, wind, and tides combine into a detailed snorkeling score for Jeju Island.
View Snorkel Forecast →