Mornings sit near the overnight low around 16°C with clear, cooler light — best for outdoor photos before crowds build.
Seoul Weather in September
Everything you need to know about Seoul weather in September
Updated September 10, 2026
Korea · Seoul
Seoul Weather in September
September in Seoul is mild, clear and pleasantly walkable. Expect daytime highs around 23°C (73°F), mild nights around 16°C, long sunny stretches, and a calmer pace than peak season Check the full climate tables below for monthly averages and packing cues.
- Avg high / low
- 23°C / 16°C
- 73F / 61F
- Precipitation
- 64mm
- 8 wet days
- Daylight
- 12.5 hrs
- mid-range daylight
Seoul average temperatures through the year
SeptemberRest of the year
5°
6°
10°
15°
20°
25°
29°
28°
23°
17°
11°
6°
JAN
8 wet
FEB
7 wet
MAR
8 wet
APR
9 wet
MAY
10 wet
JUN
11 wet
JUL
10 wet
AUG
9 wet
SEP
8 wet
OCT
7 wet
NOV
7 wet
DEC
8 wet
Daytime highs in Celsius with wet days per month for Seoul. September sits at 23°C with 8 wet days.
The short answer
September falls in Seoul's autumn. Daytime highs average 23°C (73°F) with nights near 16°C (61°F). Precipitation totals about 64mm across roughly 8 wet days. Settling snow is uncommon. Visiting works well if you plan for medium crowds Check the full climate tables below for monthly averages and packing cues Check the full climate tables below for monthly averages and packing cues.
September climate in Seoul
Monthly averages for Seoul, Korea.
- Day high
- 23°C
- 73°F
- Night low
- 16°C
- 61°F
- Precipitation
- 64mm
- 2.5 in
- Wet days
- 8
- rain or drizzle
- Sunrise
- 5:45am
- mid-September
- Sunset
- 6:15pm
- mid-range daylight
- Daylight
- 12.5 hrs
- 7 hrs sunshine
Averages based on long-run monthly climate normals. Last updated September 10, 2026.
Real weeks swing around the 20°C mean. Early September often sits near 23°C while the final week lands closer to 23°C. Pack a spare layer for that 1° drift rather than dressing only for the monthly average Check the full climate tables below for monthly averages and packing cues Check the full climate tables below for monthly averages and packing cues.
Rain and drizzle usually arrive in pulses across the 8 wet days. Dry stretches between systems feel clearer and colder overnight. Use those gaps for outdoor sightseeing and keep indoor backups for the wetter clusters Check the full climate tables below for monthly averages and packing cues Check the full climate tables below for monthly averages and packing cues.
What is the average temperature in Seoul in September?
The average temperature in Seoul in September is around 20°C (68°F), combining daytime highs of 23°C (73°F) with night lows of 16°C (61°F). The month cools steadily: the first days average highs near 23°C, while the final week typically tops out around 23°C with nights of 16°C.
Average daily high and low through September. The month cools by roughly 1 degrees start to finish.
How much does it rain in Seoul in September?
Seoul gets around 64mm (2.5in) of precipitation in September, spread over roughly 8 wet days. Wet spells typically last a day or two and clear to drier stretches in between Check the full climate tables below for monthly averages and packing cues.
64
56
64
72
80
88
80
72
64
56
56
64
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
Average precipitation by month in millimetres. September's 64mm sits near the annual rhythm.
Average precipitation by hour of day in Seoul
September precipitation in Seoul falls fairly evenly around the clock, with a mild overnight and early-morning peak. There is no predictable afternoon-downpour pattern — check the day's forecast rather than timing outings by the clock Check the full climate tables below for monthly averages and packing cues.
12am6am12pm6pm12am
Relative share of September precipitation by hour of day. The distribution is fairly flat, with a mild overnight peak.
When is sunrise and sunset in Seoul in September?
September daylight in Seoul averages about 12.5 hours, mid-range daylight. Sunrise drifts from 5:45am to 5:51am across the month, while sunset holds near 6:15pm before edging toward 6:19pm. Plan outdoor sightseeing in the brighter midday window Check the full climate tables below for monthly averages and packing cues.
Sunrise and sunset through September. The shaded band is daylight Check the full climate tables below for monthly averages and packing cues.
How humid is Seoul in September?
Relative humidity in Seoul in September averages around 62 percent. At 23°C that usually feels manageable outdoors. Temperature and wind still drive packing more than humidity alone Check the full climate tables below for monthly averages and packing cues.
60
58
55
58
62
68
70
68
62
58
55
58
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
Average relative humidity by month. September sits near 62%.
What is the weather like in Seoul the rest of the year?
Seoul moves from cooler months near 5°C highs through a warmer peak near 29°C. The best-weather stretch usually aligns with April and May. September sits in the autumn arc with 23°C highs Check the full climate tables below for monthly averages and packing cues Check the full climate tables below for monthly averages and packing cues.
Average high (coral) and low (navy) by month. The shaded band is the typical daily range; SEP is marked.
Is September a good time to visit Seoul?
Yes — if you accept medium crowds. Here is the honest trade-off.
OverallGreat for mild travel
WeatherCool and clear
CrowdsMedium
PricesMid
Budget (per night)$140 to $220
Book ahead3 to 5 weeks
September in Seoul is defined by comfortable temperatures and 23°C days. Stays often land in the $140–$220 range with mid season demand. The smartest move is to book about 3–5 weeks ahead and keep outdoor blocks in the brighter midday window Check the full climate tables below for monthly averages and packing cues Check the full climate tables below for monthly averages and packing cues.
Pros
- 23°C highs suit mild days in Seoul
- 7h average sunshine for daytime plans
- Medium crowds shape the September pace
- Mid season rates for stays and flights
Cons
- 8 wet days can pause outdoor sightseeing
- Humidity at 62% can feel heavier than the air temp
- Some attractions keep shorter winter hours
- Daylight near 12.5 hrs shortens evening walks
Travelling to Seoul in September?
Book lodgings about 3–5 weeks ahead, then visit the busiest central sights right at opening on a weekday to skip the mid-afternoon crush first-timers always hit Check the full climate tables below for monthly averages and packing cues. Compare months on our Best Time to Visit Seoul guide.
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What September actually feels like
September is Seoul's autumn in lived terms: comfortable temperatures. Most days feel cold, dry and often clear, with damper grey stretches arriving in bursts rather than settling in for the whole month Check the full climate tables below for monthly averages and packing cues Check the full climate tables below for monthly averages and packing cues.
The underestimated variable is the day–night temperature swing. It truncates outdoor evenings and pushes dinner earlier. Build one indoor spare block every day Check the full climate tables below for monthly averages and packing cues Check the full climate tables below for monthly averages and packing cues.
Early September often starts near 23°C while the final week trends toward 23°C. That 1° drift is enough to change coat weight mid-trip. Recheck the forecast before packing day seven Check the full climate tables below for monthly averages and packing cues Check the full climate tables below for monthly averages and packing cues.
Afternoons reach 23–24°C before an early sunset near the 12.5-hour daylight limit — plan open-air stops then.
Evenings cool quickly toward 16°C; shift to indoor dining and illuminated streets once the light drops.
September in Seoul, week by week
Crowds and prices move more than the thermometer.
September 1–7
23°C (73°F)- Crowds
- Medium
- Prices
- Mid season
- Best for
- Quieter weekday exploring
September 8–14
23°C (73°F)- Crowds
- Medium
- Prices
- Mid season
- Best for
- Balanced weather window
September 15–21
23°C (73°F)- Crowds
- Medium
- Prices
- Mid season
- Best for
- Steady mid-month pace
September 22–30
23°C (73°F)- Crowds
- Medium
- Prices
- Mid season
- Best for
- Late-month flexible plans
Temperatures are Seoul monthly averages split across each window. Individual years vary by several degrees.
What to pack and wear for Seoul in September
Layers for swingy days
Pack for Seoul in September around the 23°C / 16°C swing. The governing rule is stack thin layers. The one item worth buying before you fly is a breathable mid-layer Check the full climate tables below for monthly averages and packing cues Check the full climate tables below for monthly averages and packing cues.
Essential
- Light jacket
- Comfortable walkers
- Compact umbrella
- Merino mid-layer
Smart additions
- Scarf or buff
- Portable charger
- Clear tote for layers
- Lip balm SPF
Leave behind
- Thick parkas
- Wool sweaters
- Snow boots
Top places to visit in Seoul in September
Outdoor icons with shade breaks
City centre · Free
Seoul landmark walk
Go early on weekdays for quieter photos and softer light.
Add to your planWaterfront · Free
Harbour or river promenade
Golden hour is the calmest window Check the full climate tables below for monthly averages and packing cues.
Add to your planMuseum quarter · Paid
Flagship museum morning
Weekday openings beat weekend queues and wet-day backups.
Add to your planOld town · Free
Historic streets loop
Late morning light helps cold stone feel less harsh.
Add to your planPark · Free
Central green escape
Shade and benches make longer walks realistic Check the full climate tables below for monthly averages and packing cues.
Add to your planCovered market · Free
Indoor food hall backup
Ideal when wet days interrupt outdoor plans Check the full climate tables below for monthly averages and packing cues.
Add to your plan
Top places to stay in September
Base near the sights that matter in September
Best overall
Central core
Walkable to main sights with easier 12.5-hour daylight logistics Check the full climate tables below for monthly averages and packing cues.
Best value
One transit stop out
Lower rates than the core while staying close for medium evenings.
Local feel
Neighbourhood streets
Quieter nights and easier restaurant bookings than the busiest tourist blocks.
Top restaurants to visit in September
Breezy rooms and light seasonal plates
Downtown · Classic
Seoul lunch counter
Hearty midday stop when outdoor plans run short on daylight.
Add to your planOld town · Cosy
Neighbourhood bistro
Low light and early dinners match short sunset windows Check the full climate tables below for monthly averages and packing cues.
Add to your planMarket · Casual
Covered market stalls
Fast warm food without a reservation on wet afternoons Check the full climate tables below for monthly averages and packing cues.
Add to your planRiverside · Scenic
Waterfront cafe
Daylight seating works best before the evening chill Check the full climate tables below for monthly averages and packing cues.
Add to your planArts district · Modern
Gallery-side kitchen
Pairs well with museum days when weather turns Check the full climate tables below for monthly averages and packing cues.
Add to your planResidential · Local
Corner noodle or soup spot
Simple, hot bowls that suit cold or humid evenings Check the full climate tables below for monthly averages and packing cues.
Add to your plan
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Seoul weather by month
How September compares. Every month links to its full weather guide.
| Month | Avg high | Wet days | Crowds | Cost | Overall | Best for |
|---|---|---|---|---|---|---|
| January | 5°C (41°F) | 8 | Low | Budget | Avoid | Very cold, short days |
| February | 6°C (43°F) | 7 | Low | Budget | Okay | Cold but fewer crowds |
| March | 10°C (50°F) | 8 | Medium | Mid | Okay | Still chilly, early spring |
| April | 15°C (59°F) | 9 | High | High | Great | Mild spring weather |
| May | 20°C (68°F) | 10 | High | High | Great | Ideal sightseeing weather |
| June | 25°C (77°F) | 11 | High | Peak | Great | Peak tourist season |
| July | 29°C (84°F) | 10 | Very High | Peak | Okay | Hot and crowded |
| August | 28°C (82°F) | 9 | High | High | Okay | Warm, occasional storms |
| September | 23°C (73°F) | 8 | Medium | Mid | Great | Mild — this guide |
| October | 17°C (63°F) | 7 | Medium | Mid | Great | Crisp autumn days |
| November | 11°C (52°F) | 7 | Low | Budget | Okay | Cool and quiet |
| December | 6°C (43°F) | 8 | Medium | Mid | Okay | Holiday season, cold |
Temperatures shown as Seoul monthly averages.
September vs August: September averages 20°C versus 25°C in August — a 5°C cooldown. Crowds shift from High to Medium while pricing moves into mid season. Pick September if you want comfortable temperatures Check the full climate tables below for monthly averages and packing cues.
September vs October: October trends to 14°C, 6°C cooler than September. Expect medium crowds and mid season rates. Pick October if you prefer crisp autumn days Check the full climate tables below for monthly averages and packing cues Check the full climate tables below for monthly averages and packing cues.
Want September sun instead?
Need more sun than Seoul offers in September?
- 28°C
Busan in September
Milder highs near 28°C and easier outdoor days. Seoul vs Busan →
- 33°C
Jeju in September
Milder highs near 33°C and easier outdoor days. Seoul vs Jeju →
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Seoul in September FAQ
Everything you need to know about Seoul weather in September
Daytime highs average 23°C (73°F) and nights fall near 16°C (61°F). The monthly mean sits around 20°C. Expect a 1° swing from early to late September Check the full climate tables below for monthly averages and packing cues Check the full climate tables below for monthly averages and packing cues.
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Atualizado em September 10, 2026