The month in detail
What to expect in September
Autumn in Seoul is often underrated: 25°C, golden light and declining crowds. An interesting window. Rain risk remains low (22% of days), leaving good room for outdoor activities. A good balance between weather and crowds, even if June (8.3/10) remains theoretically better.
September ranks 2 out of 12 months in Seoul. Compared to August: −5°C daytime, 16 pts fewer rainy days, +1.0h of sun per day.
This month's conditions
What it's like in September
UV index
5 · moderate
protect during midday hours
Feels like
muggy at times
16°
Sea
26°C
pleasant for swimming
Daylight
12.2h of daylight
Air quality
fair
AQI 52
Compare
Is September the right month?
The best month in Seoul is June (8.3/10), 0.1 pt higher than September.
Book
Plan your trip
Hotels at their lowest outside peak season, highest on comfortable months. Shoulder seasons offer a good price/climate compromise.
Stay
Hotels & rentals · Seoul
Expedia →
Activities
Tours, tickets, experiences
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Flights
Multi-airline comparator
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🎟️ Activities & tours · Seoul
GetYourGuide selection · free cancellation
Practical info
What you need to know before you go
Three angles: the country (language, currency, safety, budget), the year-round climate, and the specifics of a beach holiday.
Country · South Korea
🗣️LanguageKorean
💶CurrencySouth Korean Won (₩)
🚗DrivingRight-hand
🛡️Safety ⓘVery safe · 1/5
💰Cost of living ⓘModerate · 3/5
🌡️ Climate
🌍Climate typeTemperate oceanic
📈Climate trend ⓘStable
🔥Hottest monthAugust · 30°C
❄️Coolest monthJanuary · 2°C
🌧️Rainiest month ⓘJuly · 43%
🏖️ Beach holiday
📅Peak seasonJuin → Sept
🏖️Swell (Sept–Mar) ⓘModérée
Explore
Other destinations in September
If September doesn't convince you for this destination, compare with others.
Location
Where is Seoul ?
Global position + regional geographic context.
🌍 World
🔍 Geographic context
South KoreaTemperate oceanic climate with a 8.3 → 4.1 gap between best and worst month. 10 years of ERA5 data to choose by project.
37.57°N · 126.98°E
Questions
Frequently asked questions
What is the best time to visit Seoul?
June is the best month with 27.0°C highs, 18.0°C lows, 6.3h of sunshine and 25.0% rainy days. The months of June & May offer comparable conditions.
How many hours of sunshine does Seoul get in June?
Seoul averages 6.3 sunshine hours per day in June. It is the sunniest month with a climate score of 7.8/10.
What is the rainiest month in Seoul?
January is the most unfavourable month with January has the lowest climate score of the year and the lowest climate score of the year.
What are the temperatures at night in Seoul in June?
In June, overnight lows reach 18.0°C, while afternoon highs average 27.0°C.
Is Seoul good in winter?
In winter (December-February), Seoul scores 4.0/10 on average — Difficult period — prefer the peak season.. The best month overall remains June with a score of 7.8/10.
When should you avoid Seoul?
January is the most difficult month to visit Seoul, with January has the lowest climate score of the year. Climate conditions are at their lowest of the year during this period.
Can you swim in Seoul in September?
In September, the sea averages 26°C in Seoul: pleasant for swimming. Swimming is pleasant without a wetsuit.
Do you need sun protection in Seoul in September?
The average UV index reaches 5 in September in Seoul (moderate), with about 12.2h of daylight. Protect during midday hours.