Question 1

Which season is wettest in Seoul?

Accepted Answer

Summer is by far the wettest season in Seoul, when the East Asian monsoon (known locally as *changma*) drives the bulk of the city's annual rainfall. During meteorological summer 2025 (June 1 to August 31), Seoul recorded 578.9 mm (22.8 in) of precipitation — roughly 44% of the entire year's total of 1,322.5 mm (52.1 in).

The rain builds steadily through the summer months. June brought 128.2 mm (5.0 in), July climbed to 216.6 mm (8.5 in), and August peaked at 234.1 mm (9.2 in) of rainfall. These warm, humid months also saw average temperatures of 25.9°C (78.6°F), so the wettest period coincides with Seoul's hottest weather.

By comparison, the other seasons in 2025 were far drier. Autumn (September to November) totaled 430.8 mm (17.0 in), spring (March to May) saw 248.2 mm (9.8 in), and the winter months of January and February were the driest with just 64.6 mm (2.5 in) combined.

For visitors, this means summer trips to Seoul should plan around sudden downpours and high humidity, with a packable rain jacket essential from June through August. Travelers seeking drier, more settled conditions will find late autumn and winter the most reliable, while spring offers a comfortable middle ground before the monsoon rains arrive.

Question 2

What were the temperature extremes in Seoul in 2025?

Accepted Answer

Seoul swung through a huge temperature range in 2025, from a peak of **38.9°C (102.0°F)** in July down to a low of **-13.8°C (7.2°F)** in January. That gives the city an annual spread of roughly 52.7°C (about 95°F) between its hottest and coldest readings.

The heat peaked in summer, with July the warmest month overall at a mean of 27.7°C (81.9°F), closely followed by August at 26.9°C (80.4°F). At the other end of the calendar, the deep cold of winter pushed February to the coldest monthly average of -2.9°C (26.8°F), while January delivered the single lowest temperature of the year. Averaged across all 12 months, Seoul's 2025 mean temperature settled at 12.5°C (54.4°F).

These extremes reflect Seoul's strongly continental, four-season climate. Monthly highs averaged 24.7°C (76.5°F) and monthly lows averaged 2.4°C (36.4°F), so visitors should pack very differently depending on timing.

For practical planning, midsummer in Seoul can feel oppressively hot and humid, and days near or above 38°C (100°F) call for hydration and shade. Midwinter, by contrast, brings sub-zero cold that often dips well below -10°C (14°F), so heavy layers are essential. The mild shoulder months of spring and autumn offer the most comfortable conditions for sightseeing in Seoul.

Question 3

When is the sunniest time of year in Seoul?

Accepted Answer

The sunniest time of year in Seoul is the summer, peaking in July, which recorded **289.9 hours of sunshine** in 2025 — about 9.4 hours per day. Across the full year, Seoul accumulated **2,819 hours of sunshine** in 2025, averaging roughly 7.7 hours of sun each day.

The summer months (June to August) were the brightest stretch overall, totaling **860 hours**, or about 9.3 hours of sunshine daily. The top three sunniest months were all consecutive:

- **July 2025:** 289.9 hours (warmest at 27.7°C / 81.9°F)
- **August 2025:** 286.7 hours (26.9°C / 80.4°F)
- **June 2025:** 283.4 hours (23.1°C / 73.6°F)

There is an important catch, though. Although these summer months in Seoul deliver the most raw sunshine hours, they also bring the heaviest rain — July saw 216.6 mm and August 234.1 mm of precipitation in 2025, reflecting the East Asian monsoon. The light arrives in long bright spells punctuated by heavy downpours.

For travellers who want plenty of sun with far less rain, spring is the sweet spot: April 2025 logged a strong 271.9 hours of sunshine alongside milder temperatures of 11.4°C (52.5°F). At the other end, October was the cloudiest month of 2025 with only 156 hours of sun.

In short, if your priority is maximum daylight in Seoul, aim for July; if you want sunshine with comfortable, drier conditions, plan your visit for April or late spring.

Question 4

How cold does Seoul get in January?

Accepted Answer

January is the coldest month in Seoul, with an average temperature of **-2.4°C (27.6°F)** in January 2025 and most days staying below freezing.

Across the 31 days of January 2025, daily highs averaged just 2.2°C (36.0°F) while overnight lows dropped to an average of -6.4°C (20.5°F). The mean temperature stayed below 0°C on 23 of the month's 31 days, so sub-zero conditions were the norm rather than the exception in Seoul.

The cold peaked during an Arctic spell in early January 2025. The coldest reading of the month was -13.8°C (7.2°F) on January 10, and temperatures dipped to -10°C (14°F) or lower on 5 separate nights. The mildest moment came on January 25, when the thermometer reached 8.2°C (46.8°F) during a brief thaw.

January in Seoul is dry as well as cold, recording only 16.5mm (0.65 in) of precipitation across 6 days, with average humidity of 65% and light winds averaging 6.6 km/h (4.1 mph).

For visitors, this means Seoul in January demands serious winter gear: insulated coats, hats, and gloves are essential, especially after dark when wind chill makes the cold bite harder. The upside is plenty of crisp, dry, sunny days that are well suited to sightseeing, palace tours, and the city's outdoor ice-skating rinks.

Question 5

How hot and humid does Seoul get in summer?

Accepted Answer

Seoul gets hot, sticky, and intense in summer, with a 2025 summer (June–August) average temperature of 25.9°C (78.6°F) and humidity averaging 75%. The combination of heat and moisture, driven by the East Asian monsoon, makes the season feel far warmer than the numbers alone suggest.

July and August are the peak of the heat in Seoul. In 2025, July averaged 27.7°C (81.9°F) and August 26.9°C (80.4°F), while June was milder at 23.1°C (73.6°F). Daily highs across the season averaged 30.7°C (87.3°F), and the hottest day of the year landed on July 29, 2025, when temperatures peaked at 38.9°C (102.0°F).

A few specific figures show just how oppressive Seoul's 2025 summer was:

- **55 days** reached 30°C (86°F) or higher
- **15 days** hit at least 35°C (95°F)
- **12 tropical nights** stayed above 25°C (77°F), with August humidity climbing to 81%

These hot, humid conditions in Seoul mean lightweight clothing, sun protection, and good hydration are essential for summer visitors. Indoor attractions, air-conditioned cafés, and early-morning or evening sightseeing are the most comfortable options, since midday heat combined with high humidity can be draining. Travelers hoping for cooler, drier weather may prefer Seoul's spring or autumn, but those who don't mind the warmth will find the city lively throughout the season.

Sŏngsuilgail-tong

Seoul

FAQ

Which season is wettest in Seoul?

What were the temperature extremes in Seoul in 2025?

When is the sunniest time of year in Seoul?

How cold does Seoul get in January?

How hot and humid does Seoul get in summer?