During the week of 20 October 2025 - 26 October 2025, temperatures averaged at 21 °C (70 °F) during the day and dropped to 17 °C (63 °F) at night. These temperatures are roughly same as the long-time average for Jeju, being 22 °C (72 °F) for daily temperatures and 15 °C (59 °F) for night temperatures. The average temperatures observed during different times of day (based on local time) were as below: 7am 18 °C (64 °F), 10am 19 °C (66 °F), 1pm 20 °C (68 °F), 4pm 20 °C (68 °F), 7pm 19 °C (66 °F), 10pm 19 °C (66 °F).

There were 5 days without rain, 1 day with light rain and 1 day with moderate rain during this week. Jeju received 1 mm (0.04 in) of precipitation throughout the week, which is below its long-term average of 17 mm (0.67 in). From dawn to dusk, there was an average of 61 % cloud coverage during the day.

Average speed of wind was 4.6 m/s. Prevailing wind direction(s) were North and North-East. The air pressure varied between 1018 hpa and 1026 hpa. On average, the air humidity in Jeju was 68 %.

During the daytime (from dawn to dusk), there were in average: 2 hours clear skies, 1 hour partially overcast skies, 8 hours overcast skies and 0.5 hours rainy weather. On average, the time of sunrise was 06:44, and the time of sunset was 17:51.

Weather overview

Jeju (South Korea) is a place with a mild climate. The day temperatures range from 8 °C (46 °F) in January to 30 °C (85 °F) in August. The least rainy month in Jeju is October with its 6 days of rain, the rainiest month is August, when it rains 13 days. The highest sea temperatures in Jeju are in August with 27 °C (80 °F) and the lowest in March with 13 °C (56 °F). The highest night temperatures could be experienced in August with 24 °C (75 °F), the lowest in January with 3 °C (37 °F).

January weather

The minimum of the day temperature is observable in Jeju, while the sea temperature continues to descent, with its value of 15 °C (59 °F). The rainfall amount rise's start could be observed, its value is 65 mm (2.57 in). The night temperature is on its minimum, the value of this measure is 3 °C (37 °F). The minimum of the number of sun hours (without clouds) is observable, with its value of 4 hours.

February weather

The day temperature starts to rise, the value of this measure is 9 °C (49 °F) in Jeju, while the descent of the sea temperature can be observed, with its value of 14 °C (57 °F). The number of rainy days starts to rise, with its value of 8 days, while the rainfall amount continues to rise, its value is 73 mm (2.89 in). The beginning of the rise of the night temperature could be noticed, with its value being 3 °C (38 °F). The number of sun hours (without clouds) starts to rise in February.

March weather

The day temperature continues to rise, with its value of 13 °C (55 °F) in Jeju, while the minimum of the sea temperature is observable, the value of this measure is 13 °C (56 °F). The rainfall amount rises similarly to the previous month, its value is 109 mm (4.30 in). The rise of the night temperature can be observed, with its value being 6 °C (43 °F). The rise of the number of sun hours (without clouds) can be observed, its value is 6 hours. The humidity is on its minimum, with its value of 69 %.

April weather

The sea temperature rise's start could be observed, its value is 14 °C (58 °F) in Jeju, while the day temperature rises similarly to the previous month, with its value being 18 °C (64 °F). The night temperature rises similarly to the previous month, the value of this measure is 10 °C (50 °F). The rise of the rainfall amount can be observed, with its value being 134 mm (5.26 in). The number of sun hours (without clouds) rises similarly to the previous month, the value of this measure is 7 hours.

May weather

The day temperature rises similarly to the previous month, the value of this measure is 21 °C (71 °F) in Jeju, and the rise of the sea temperature can be observed too, with its value being 16 °C (61 °F). The rainfall amount continues to rise, its value is 166 mm (6.54 in). The number of sun hours (without clouds) continues to rise, its value is 7 hours. The night temperature continues to rise, its value is 14 °C (58 °F).

June weather

The tourist season slowly starts in Jeju. The rise of the day temperature can be observed, the value of this measure is 25 °C (76 °F), and the rise of the sea temperature can be observed too, the value of this measure is 20 °C (67 °F). The number of rainy days starts to rise, the value of this measure is 11 days, while the rainfall amount continues to rise, with its value being 233 mm (9.17 in). The night temperature continues to rise, the value of this measure is 19 °C (66 °F).

July weather

The rise of the day temperature can be observed, with its value being 29 °C (83 °F) in Jeju, and the sea temperature rises similarly to the previous month too. There is pending tourist season. The number of rainy days rises similarly to the previous month, while the rainfall amount reaches its maximum, the value of this measure is 283 mm (11.16 in). The night temperature continues to rise, with its value of 23 °C (74 °F).

August weather

There is pending tourist season in August in Jeju. The sea temperature reaches its maximum, its value is 27 °C (80 °F), and the day temperature reaches its maximum as well, with its value of 30 °C (85 °F). The number of rainy days reaches its maximum, with its value of 13 days. The night temperature is on its maximum in August. The maximum of the number of sun hours (without clouds) can be noticed, its value is 7 hours.

September weather

The tourist season continues in Jeju. The beginning of the descent of the day temperature could be noticed, its value is 26 °C (79 °F), and the beginning of the descent of the sea temperature could be noticed as well, the value of this measure is 25 °C (76 °F). The rainfall amount continues to descent, with its value being 187 mm (7.37 in), while the number of rainy days descent's start could be observed, with its value being 10 days. The beginning of the descent of the number of sun hours (without clouds) could be noticed in September.

October weather

The ongoing tourist season is noticeable in Jeju. The day temperature continues to descent, with its value of 22 °C (71 °F), and the sea temperature continues to descent too, its value is 22 °C (71 °F). The rainfall amount descents similarly to the previous month, its value is 74 mm (2.92 in), while the minimum of the number of rainy days can be noticed in this month. The night temperature continues to descent, its value is 15 °C (58 °F).

November weather

The descent of the sea temperature can be observed, the value of this measure is 19 °C (65 °F) in Jeju, and the day temperature continues to descent as well, with its value being 16 °C (60 °F). The beginning of the rise of the number of rainy days could be noticed, its value is 8 days. The number of sun hours (without clouds) starts to descent in November. The night temperature descents similarly to the previous month, with its value being 9 °C (48 °F).

December weather

The sea temperature continues to descent in Jeju, and the day temperature descents similarly to the previous month as well, with its value being 11 °C (51 °F). The rainfall amount is on its minimum, with its value of 51 mm (2.00 in). The night temperature continues to descent, with its value being 5 °C (40 °F). The day length is on its minimum in this month. The wind speed is on its maximum, its value is 6.

What is the air temperature in April in Jeju at night?

The average night temperature in Jeju in April is 10 °C (50 °F). Nights can be cooler, morning running can be refreshing but choose appropriate clothing, evening outdoor sitting can be pleasant but you can also be cold.

How many rainy days can I expect in May in Jeju?

In May in Jeju, we can expect 9 days to be rainy, that is, days when precipitation exceeds 2 mm (0.08 in). Converted to days of the week, this means that it will occur on an average of 2.0 days of the week, or in general - 29 % days.

Are there good conditions to visit in Jeju in June?

There are good conditions for visiting in Jeju in June. The temperature during the day will be nice 25 °C (76 °F). At night, temperatures hover around a pleasant 19 °C (66 °F). A sea temperature of 20 °C (67 °F) can seem colder to some, but others will call it refreshing.

What is the sea temperature in Jeju in July?

In July in Jeju expect the sea to be warm at 24 °C (75 °F). This warm sea is nice for swimming, maybe cold for some, but most people can spend a long time in it.

Is it hot in Jeju in August?

In Jeju in August, you will enjoy nice warm weather, but it will also be pleasant and you probably won't feel hot.

Is September part of the wet season in Jeju?

No, there is no wet season in Jeju in September - you can expect 10 days of rain during the month.

What temperature can I expect during the day in Jeju in October?

The average daily temperature in October in Jeju is 22 °C (71 °F). A comfortable temperature for most people, where it is neither too cold nor too hot, and a large number of activities can be carried out comfortably, including sunbathing by the water. Lighter clothing will be suitable - shorts, skirts, t-shirts, jackets; a light sweater and long trousers may also be useful.