Thinking about a summer trip to Seoul? You’ll want to brace yourself for hot, sticky days and plenty of rain. Daytime temperatures usually land somewhere in the mid-20s to around 30 °C (mid-70s to mid-80s °F), with July and August turning up the heat and the rainfall. The season feels nothing like Seoul’s crisp autumns or bone-chilling winters.
You’ll get long daylight hours, high humidity, and those sudden monsoon downpours that define the East Asian monsoon. Sure, the rain can be intense, but it often comes and goes, leaving behind stretches of warm sun.
These swings give summer in Seoul a rhythm all its own. Locals and visitors adjust their days around the weather’s unpredictability.
Knowing what to expect helps you pack smarter—think lightweight clothes, an umbrella, and maybe some flexible plans for outdoor adventures. If you keep an eye on the temperatures, rainfall, humidity, and wind, you’ll get more out of your time in South Korea’s capital.
Overview of Seoul’s Summer Climate
Seoul’s summers? Hot, humid, and rainy, thanks to the East Asian monsoon. You’ll deal with frequent showers, muggy air, and temperatures that barely drop at night.
The season stands out from Seoul’s dry, cold winters and those gentle spring and autumn months.
Climate Classification and Location
Seoul sits up in northwest South Korea, not too far from the Yellow Sea. Its climate is humid continental, so summers get warm or even hot, while winters turn cold and dry.
Because Seoul is inland, you’ll notice bigger temperature swings than you would by the coast.
In the summer, warm tropical air masses take over. They collide with cooler continental breezes, which makes for unstable, rainy weather.
The city’s dense urban sprawl adds to it. Concrete and asphalt trap heat, so nighttime temperatures stay up compared to the countryside.
This “urban heat island effect” means summer evenings in Seoul often feel warmer than you’d expect from the forecast. Add in the humidity, and muggy nights can feel downright stifling—without air conditioning, it’s a challenge.
Typical Summer Weather Patterns
From June to August, Seoul hits its steamiest, wettest stretch. Average daytime highs run from 27 °C to 30 °C (81 °F to 86 °F), and nights stay warm, usually around 22 °C (72 °F).
Heatwaves sometimes push the mercury above 35 °C (95 °F), especially on the roughest days.
Most of the rain falls in July and August, right when the monsoon is at its peak. July alone can dump more than 400 mm (16 in) of rain, usually in short, heavy bursts.
Expect cloudy skies about half the time. Sunshine hours hit their lowest point of the year.
Humidity often climbs over 70%, so the air feels thick. Typhoons sometimes reach Korea from late summer into early autumn, bringing strong winds and extra rain.
Seoul doesn’t get hit as hard as the southern coast, but it’s still something to watch for.
Comparison to Other Seasons
Summer in Seoul doesn’t feel anything like the rest of the year. Winters get cold and dry, with highs around 2 °C (36 °F) in January and hardly any rain or snow.
Spring, from March to May, brings milder weather and a little more rain. Many people say it’s the best time to visit—comfortable temperatures and blooming landscapes.
Autumn, especially September and October, cools off and dries out after the monsoon. Rain drops off, skies clear, and highs settle around 20 °C (68 °F) by October.
The air turns crisp, and the city bursts into color, drawing lots of travelers.
Compared to these seasons, summer stands out for its heat, humidity, and heavy rain. It’s a distinct, sometimes challenging stretch.
Average Summer Temperatures in Seoul
Summer in Seoul means hot days, warm nights, and high humidity. Temperatures rise steadily from June through August, with July and August really turning up the heat.
Monthly Daytime and Nighttime Temperatures
In June, daytime highs usually hit 23°C to 27°C (73°F to 81°F). Nights stay pretty mild, averaging 18°C to 20°C (64°F to 68°F), so early summer feels a bit more tolerable.
By July, days warm up to 28°C to 29°C (82°F to 85°F). Nights don’t cool off much, hovering near 21°C to 23°C (70°F to 73°F).
August keeps the same pattern, with highs around 29°C (85°F) and lows close to 22°C (72°F). Nights can feel sticky, and air conditioning becomes a must for many.
| Month | Avg High (°C/°F) | Avg Low (°C/°F) |
|---|---|---|
| June | 23–27 / 73–81 | 18–20 / 64–68 |
| July | 28–29 / 82–85 | 21–23 / 70–73 |
| August | 29 / 85 | 22 / 72 |
Hottest Months of the Year
July and August are easily the hottest months in Seoul. Highs often climb past 29°C (85°F), and with the humidity, it feels even hotter than the numbers say.
Nights rarely drop below 21°C (70°F), so there’s not much relief after sunset.
Humidity peaks now, making things feel extra sticky. Plan on taking cooling breaks indoors if you’re out and about.
If you’re sightseeing, don’t forget the UV index is very high. Sun protection is a must, and it’s smart to pace yourself—these conditions can really sap your energy.
Humidity Levels During Summer
Seoul’s summer packs both high temperatures and high humidity. July and August bring especially sticky weather, a big jump from the drier spring and winter.
Average Humidity by Month
Humidity really ramps up as summer gets going. In June, average relative humidity sits around 70%, already feeling damp compared to earlier months.
By July, it peaks at about 77%, the highest point of the year. August stays humid too, averaging close to 75%.
This pattern comes from the East Asian monsoon. Moist ocean air moves inland, bringing lots of rain and cloudy skies.
Warm temperatures and high moisture combine to make the air feel heavy.
Here’s a quick look:
| Month | Average Humidity |
|---|---|
| June | ~70% |
| July | ~77% |
| August | ~75% |
You’ll rarely get dry air during a Seoul summer.
Impact of Humidity on Comfort
High humidity really changes how heat feels on your skin. When it’s above 70%, sweat doesn’t evaporate well, so you feel hotter than the thermometer says.
Walking or sightseeing outdoors can get tiring fast.
Indoors, you’ll notice a big difference. Air conditioning is everywhere—hotels, shops, public transit—but the shift from muggy streets to cool interiors can be jarring.
Carrying water and wearing light, breathable clothes goes a long way to stay comfortable.
If you’re planning to hike, visit markets, or explore outside, mornings and evenings are usually nicer. Midday can feel pretty punishing with the heat and humidity.
Tweaking your schedule to avoid the worst of it makes a big difference.
Summer Precipitation and Rainfall Patterns
Seoul’s summers get drenched, especially in the middle of the season. You’ll see sharp differences between wetter and drier months, with lots of rainy days that shape daily routines and travel plans.
Monsoon Season and Rainfall Peaks
Rainfall jumps up from late June through August, all thanks to the East Asian monsoon. July is the wettest month, averaging about 316 mm of precipitation—that’s more than ten times what January gets.
You’ll see short but heavy downpours, not long drizzles. Streets can flood fast, and humidity stays high all day.
August is still very wet, with totals often over 300 mm. June and September see less, but it’s still enough to notice.
By late September, the monsoon backs off and things start to dry out.
For a quick comparison:
| Month | Average Precipitation (mm) |
|---|---|
| June | ~133 mm |
| July | ~316 mm |
| August | ~300 mm |
| September | ~169 mm |
If you’re planning outdoor activities, expect sudden weather changes and keep your plans flexible.
Number of Rainy Days
It’s not just the amount of rain—the number of rainy days spikes in summer. July averages 16 days with measurable rain, and August usually has 14–15 days.
The rain doesn’t last all day. Many times, you’ll only get a few hours of heavy showers, often in the afternoon or evening.
That means you can still enjoy mornings or late nights with less interruption.
June brings about 9–10 rainy days, and September drops to 9–11 days as things wind down.
Most of the rain falls in just a few months, not spread out through the year. So, if you’re visiting in July or August, plan for wet weather—it matters way more than in other seasons.
Wind Conditions in Seoul’s Summer
Summer winds in Seoul usually stay gentle, with small shifts in direction depending on the month. These breezes can make the humidity feel a bit different and impact how comfortable it is outdoors.
Average Wind Speed and Direction
Expect average wind speeds between 2 to 3 meters per second (about 4.5 to 6.7 mph). That’s light—rarely enough to disrupt anything.
Winds mostly blow from the south or southeast in summer, bringing in warm, moist air from the sea. That just adds to the city’s humidity.
Here’s a quick look:
| Month | Avg. Wind Speed | Common Direction |
|---|---|---|
| June | ~2.5 m/s | South/Southeast |
| July | ~2.7 m/s | Southeast |
| August | ~2.6 m/s | South/Southwest |
You’ll notice the breeze most in open spots, like Han River parks. In the city center, tall buildings block or redirect the wind, making the air feel even more still.
Effects of Wind on Weather Experience
With these light winds, you often feel the full force of Seoul’s heat and humidity. When breezes die down, hot days can feel even worse.
Southern winds also help drive the rainy season by bringing in moisture that fuels monsoon rains.
On clearer days, even a mild wind can offer some relief. Open spaces get cooler evenings, while dense neighborhoods can feel stuffy.
If you’re planning to be outside, expect calm winds—not gusty ones. Parks, riverside walks, and festivals usually stay comfortable, though you’ll still have to deal with muggy air, especially when the wind drops.
Best Time to Visit Seoul in Summer
Visiting Seoul in summer brings a mix of lively festivals and tough weather. The best time to go depends on how well you handle heat, humidity, and the seasonal rains that shape the city’s summer vibe.
Weather Considerations for Travelers
Summer in Seoul usually runs from June through August. You’ll see average highs between 25°C and 35°C (77°F–95°F).
July gets the hottest and, honestly, the wettest. The monsoon season often brings heavy rain from late June into mid-July.
If you want to dodge the worst heat, early June feels more comfortable. You’ll get longer daylight and not as many rainy days.
Late August also feels easier, since temperatures start to drop, but festivals are still happening.
Humidity really makes a difference. It often climbs over 70%, so the air feels even warmer than what the thermometer says.
Poor air circulation in the city center can make things worse, especially when you’re in crowded spots.
A lot of travelers say the best time to visit Seoul in summer is either early June or late August. These windows give you warm weather but fewer headaches from heavy rain or extreme heat.
Tips for Enjoying Seoul’s Summer
Honestly, you’ll want to pack light, breathable clothing—think cotton shirts or linen pants. Don’t forget a hat, sunglasses, and some sunscreen if you plan to be out and about.
I always toss a compact umbrella or a light rain jacket in my bag, especially if I’m visiting during those unpredictable monsoon weeks. It’s just easier that way.
If you’re heading to places like Gyeongbokgung Palace or Hangang Park, try going early in the morning or later in the evening, when it’s not as hot. Save the museums, shopping in Myeongdong, or exploring Dongdaemun Design Plaza for the midday hours when the sun can get brutal.
Stay hydrated—just carry a reusable water bottle. Convenience stores and vending machines are everywhere, so it’s never hard to refill.
When you need to cool down, grab some naengmyeon (those cold noodles) or patbingsu, the shaved ice dessert. Locals love them for a reason, and honestly, they’re perfect for Seoul’s summer heat.
The subway system has air conditioning, so public transport actually feels like a break from the weather. Pick up a T-money card, and you’ll move around easily without standing outside for ages buying tickets.