Fall in Seoul, South Korea really changes the vibe of the city. Average daily highs slide down from late-summer warmth to cool, crisp days by late November, and lows go from pleasant evenings to nights that nearly freeze.
This steady shift makes autumn one of the most comfortable and scenic times to get out and see the capital.
You’ll notice a lot less rain than during the summer monsoon season. Precipitation chances drop off fast as the weeks go by.
Skies clear up more often, so you get brighter days and more sunshine. Shorter daylight, cooler air, and drier weather combine to create a season that feels refreshing and easy to plan around.
If you care about temperature swings, rainfall, or how many daylight hours you’ll get, knowing the average fall weather in Seoul helps you prep for everything from city strolls to mountain hikes.
This balance of clear skies and mild weather makes it a fantastic time to be outdoors in South Korea’s capital.
Overview of Fall Weather in Seoul
Fall in Seoul brings cooler air, lower humidity, and clearer skies compared to summer.
Rainfall drops off sharply as the season goes on. Daylight hours shrink quickly as winter nears.
Typical Fall Climate Patterns
September still feels a bit like summer, with daytime highs around 75–80°F (24–27°C).
By late November, daytime temperatures usually fall to the 40s°F (5–10°C), and nights get close to freezing.
This steady drop makes fall one of the most obvious seasonal changes in Seoul.
Humidity shifts too. Early fall can still feel muggy, but by mid-October, the air turns crisp and dry.
The odds of muggy weather go from over 50% in early September to almost 0% by late November.
Rainfall drops fast. September averages about 8 inches (200 mm), but by November, you might only see 1 inch (25 mm).
October and November usually end up as some of the driest months.
Clouds thin out as well. Early fall brings a lot of overcast days, but by mid-October, sunshine is more common.
The clearest days usually show up in the second half of October, when you get about a 70% chance of clear or partly cloudy skies.
Seasonal Weather Transitions
As fall moves along, you’ll notice shorter days and cooler nights.
Daylight slips from nearly 13 hours in early September to under 10 hours by late November.
Sunsets happen earlier, moving from about 7:00 PM in September to just after 5:00 PM in late November.
Winds shift, too. Early fall winds blow in from the east, but by November, they come from the north and west, bringing colder air.
Average wind speeds rise a bit, from 7 mph to 9 mph as autumn goes on.
Water temperatures near Seoul cool off quickly. Early September sees surface water at about 76°F (24°C), but by late November, it drops to 53°F (12°C).
This cooling really signals that winter is on the way.
By mid-November, frost starts to show up more often, and the growing season wraps up.
If you’re visiting, you’ll want a light jacket in September, a heavier coat by November, and something in between for those perfect fall walks.
Average Temperatures in Fall
During fall in Seoul, both daytime highs and nighttime lows steadily drop. The season starts off warm and ends feeling almost wintry.
You might not notice the change day-to-day, but the difference between early and late fall is pretty dramatic.
Daily High and Low Temperatures
In September, average highs hit the upper 70s °F (about 25–26°C), and lows hover in the mid-60s °F (18–19°C).
By November, highs land in the mid-40s °F (7–8°C), and lows dip to the low 30s °F (0–1°C).
That’s a pretty sharp cooling, meaning you might start the season in short sleeves and end it bundled up.
The overall drop is about 36°F for highs and 37°F for lows from start to finish.
If you’re planning to spend time outdoors, keep this in mind. Early fall evenings stay comfortable, but by late November, frost and chilly mornings are the norm.
Monthly Temperature Trends
Monthly averages really show the change.
- September: Highs 24–26°C (75–79°F), lows 17–19°C (63–66°F).
- October: Highs 18–20°C (64–68°F), lows 9–11°C (48–52°F).
- November: Highs 9–12°C (48–54°F), lows 1–3°C (33–37°F).
October usually feels the nicest, with crisp air and mild afternoons.
By November, temperatures get close to winter levels, and you might see the first frost.
These numbers help you see how fast things cool off. If you visit early in the season, you’ll have warmer days, but late fall is a whole different story.
Temperature Fluctuations by Day and Night
The gap between day and night temperatures widens as fall goes on.
Early in the season, nights are just a bit cooler than days. By November, nights can be more than 15°F colder than the afternoon.
You might feel warm in the sun but need a heavier jacket after dark.
Colder nights also mean the growing season is wrapping up, as soil cools and plants slow down.
If you’re outside in Seoul, expect mild afternoons in September and October, but plan for brisk evenings.
By late fall, mornings often start near freezing, even if the afternoon warms up a bit.
Rainfall and Precipitation Patterns
Autumn in Seoul sees rainfall dropping off quickly after the heavy summer monsoon.
You’ll notice a steady shift from frequent wet days in September to much drier conditions by November.
Both the amount and type of precipitation change as it gets colder.
Probability of Wet Days
September still carries some leftover monsoon energy.
You’ve got about a 30–35% chance of measurable rain on any day, so roughly one in three days might bring showers or storms.
By October, chances drop to around 15%. Rain becomes less frequent, and crisp, dry days take over.
November brings even fewer wet days, averaging less than 10%. The city can go many days in a row with no measurable rain.
Wet day probability at a glance:
- September: ~30–35%
- October: ~15%
- November: <10%
Monthly Rainfall Totals
Rainfall amounts in Seoul keep falling through autumn.
September averages 150–200 mm, still a decent amount but much less than summer’s peak.
October drops to about 40–50 mm, usually in short, scattered showers.
By November, you’re looking at only 20–30 mm. It’s one of the driest months, with light rain or drizzle more common than heavy downpours.
| Month | Average Rainfall | Typical Rain Pattern |
|---|---|---|
| September | 150–200 mm | Leftover monsoon showers |
| October | 40–50 mm | Short, scattered showers |
| November | 20–30 mm | Light rain, occasional mist |
Types of Precipitation in Autumn
In September and early October, almost all precipitation comes as rain.
Thunderstorms can still pop up, but they’re not as intense as in summer.
By late October, cooler nights sometimes bring drizzle or mist, especially in the mornings.
This usually happens when it’s chilly but not freezing.
In November, you might spot the first hints of winter. Most days stay dry, but light snow or a mix of rain and snow can show up, especially late in the month.
These wintry events are usually brief and don’t really stick.
The shift from heavy rain to light snow marks Seoul’s move from humid summer to cold, dry winter.
Cloud Cover and Sunshine Hours
Fall skies in Seoul clear out as the months go by, and daylight hours shrink fast.
You’ll see fewer overcast days and a steady loss of sunlight as winter approaches.
Changes in Cloudiness
Cloud cover drops quickly from early to late fall.
In early September, the sky is overcast or mostly cloudy about 46% of the time.
By late November, that falls to around 33%.
The clearest stretch usually comes in mid-October, with October 20 often being the day with the least cloud cover.
On that day, skies are clear, mostly clear, or partly cloudy about 71% of the time.
Compared to summer, when July can bring over a 50% chance of overcast skies, fall days feel noticeably brighter.
This makes outdoor activities and sightseeing much more appealing, especially in October when the air is crisp but not freezing.
Average Daily Sunshine
Even as skies clear up, daylight hours shrink quickly.
Early September gives you nearly 13 hours of daylight, but by late November, it’s under 10 hours.
Seoul gets about 5 to 6 hours of direct sunshine per day in September.
By November, this drops to around 4 hours per day as days get shorter and the sun sits lower.
So, while you get clearer skies, there’s less total sunlight as fall goes on.
It’s smart to plan outdoor activities earlier in the day, especially in late fall when sunset comes before 5:30 PM.
Daylight Duration and Sun Position
In Seoul during fall, daylight hours keep shrinking, and the sun’s angle drops lower.
These changes affect how much sunlight you get and when you’ll want to be outside.
Daylight Hours Across Fall
Daylight in Seoul drops fast from early to late fall.
September gives you about 12 hours and 22 minutes of daylight each day.
By October, it’s around 11 hours and 8 minutes, and in November it slips to about 10 hours and 6 minutes.
Direct sunshine shifts too. September averages 6 hours and 54 minutes of sun per day, while October actually bumps up to 7 hours and 27 minutes since skies are clearer.
By November, you get closer to 6 hours.
The sun’s altitude at midday also dips. In September, it climbs to about 53° above the horizon, but by November, it only reaches around 32°.
This gives the city longer shadows and a cooler feel. You’ll notice it in parks and on the streets—the sun just sits lower.
Sunrise and Sunset Times
Sunrise and sunset both happen earlier as fall goes on.
Early September brings sunrise around 6:00 AM and sunset near 6:30 PM.
By mid-October, sunrise moves to about 6:30 AM and sunset to 5:45 PM.
Late November sees sunrise close to 7:10 AM and sunset around 5:15 PM.
Evenings get darker faster, which can change your plans for dining, walking, or sightseeing.
Morning light also comes later, so you might want to adjust your schedule if you’re heading out early.
The lower midday sun and shorter days create a softer light—great for photography, honestly.
It really marks the change from the bright, long days of summer to the short, cool days of winter in Seoul.
Additional Weather Factors in Autumn
During autumn in Seoul, a few other weather factors shape your experience.
Wind patterns shift, humidity drops quickly, and seasonal air quality can influence your outdoor plans.
Wind Speed and Direction
Winds in Seoul start off gentle, but they pick up as autumn rolls in. Average speeds go from about 7 mph in early September up to nearly 9 mph by late November. That steady breeze isn’t extreme, but it definitely makes evenings feel a bit chillier.
You’ll probably notice the wind direction changing, too.
- September to early October: winds usually come in from the east.
- Mid-October to mid-November: they start blowing in from the west.
- Late November: winds often arrive from the north, bringing in colder air.
When those northerly winds show up late in the season, you can tell winter’s just around the corner. If you’re heading outdoors—maybe hiking in the nearby mountains—layer up so you can handle both the chill and the wind.
Humidity Levels
Humidity in Seoul drops off fast once summer ends. In early September, more than half the days might still feel muggy, but by late October, that almost never happens. The air turns crisp and comfortable, especially during the day.
Lower dew points mean sweat dries off quicker, so you won’t feel as sticky as you did in the summer. Nights can surprise you by feeling cooler, since dry air lets heat escape faster.
If you’re sensitive to dry air, you might notice dry skin or a scratchy throat by November. Using a small humidifier at home or keeping a water bottle handy helps a lot. Honestly, many travelers say autumn is one of the best times to explore Seoul—mostly thanks to this drop in humidity.
Air Quality and Yellow Dust Events
Seoul’s air quality usually gets better after spring. That’s when yellow dust storms from China and Mongolia tend to hit more often.
Autumn tends to bring clearer skies. Still, you might notice the air isn’t always perfect—sometimes pollution episodes pop up out of nowhere.
Winds can blow urban smog right into the city basin, and that makes fine particulate matter (PM2.5) spike. It doesn’t happen as much as it does in winter, but on calm days, you’ll probably spot some haze that cuts down visibility.
Yellow dust events almost never happen in autumn. Every now and then, though, strong winds in late November can sweep dust in from the west.
If that happens, you might get alerts telling you to wear a mask or skip your jog outside. It’s honestly just smart to check daily air quality apps, especially if you have asthma or allergies.