Seongnam Weather in September

September in Seongnam brings high temperatures, with daytime highs of 27°C (81°F) and nights around 16°C (61°F). Quite a bit of rainfall is expected, around 136 mm (5.4 in), so pack an umbrella.

Rainfall in Seongnam in September

Typically, about 9 days will experience rainfall, with an average of 136 mm (5.4 in) for the month. When it rains this month, it tends to come down fairly heavily. Showers can be substantial even if they don't last all day.

Temperature in Seongnam in September

Seongnam in September gets highs of 27°C (81°F) during the day and drops to 16°C (61°F) at night. Overall, the month follows a fairly predictable daily temperature pattern. At 16°C (61°F) overnight, it can feel quite a bit cooler after dark. Worth packing something warmer for evenings, but the cooler temperatures are ideal for sleeping.

Sunshine in Seongnam in September

The city usually sees around 182 hours of sunlight, indicating a moderately sunny period.

Wind Speed in Seongnam in September

Wind speeds average 2 m/s (4 knots) during September. At this speed, expect light breezes that you can feel on your face and cause leaves to rustle gently. Since this is an average, some days are calmer with barely any wind while others have more noticeable gentle breezes.

For Seongnam itself, October generally stands out with the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.

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For a detailed overview over the year and the best time to visit South Korea, check out our Seongnam's climate page.

Seongnam Temperature in September

Min Temperature 16°C (61°F)  

Max Temperature 27°C (81°F)  

Chance of Rain 28%  

Precipitation 136 mm (5.4 in)  

Rainy days 9 days  

Humidity 67% *  

Windspeed 2 m/s (4 knots) *  

Sunshine 182 hours *  

Percentage Sunshine 48% *  

* Data from: Seoul, South Korea (20 KM, 12 Miles).

Daily Historical Temperatures

50-year average (1976-2025)

Based on our historical records, temperatures in Seongnam typically drop from around 28°C (82°F) at the start of September to approximately 24°C (75°F) by the end. Nights are pleasant, with lows typically ranging from 13°C (55°F) to 20°C (68°F).

Average temperatures in September

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Daily Historical Precipitation

50-year average (1976-2025)

Average daily rainfall for each day of the month based on long-term records.

Average precipitation in September

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Historical weather for Seongnam in September

Browse day-by-day weather records for Seongnam spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.

Historical weather Temperatures Precipitation

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Seongnam historical weather extremes in September

Based on 49 years of weather observations in Seongnam between 1976 and 2025, these are the recorded extremes.

• Seongnam recorded its highest September temperature of 34°C (93°F) on September 11, 2024.
• Seongnam experienced its chilliest September day on September 25, 1997, reaching only 17°C (63°F).
• The coldest night in September in Seongnam was on September 22, 1977, with a minimum of 5°C (41°F).

What to Wear in Seongnam in September

Warm weather calls for comfortable, breathable clothing in September. Cotton t-shirts, shorts, light dresses, and sandals are perfect. You might still want a light layer for evenings or air-conditioned places (for example buses). High rain levels are expected, so pack waterproof gear and an umbrella or poncho. It won't hurt to bring your sunglasses along, as you'll see some sunny periods.

What To Do in Seongnam in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

7/10

Cycling

7/10

Walking

7/10

Camping

6/10

Outdoor sports

7/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit South Korea, check out our Seongnam's climate page.

More climate data for Seongnam

Temperature Rainfall Sunshine Humidity Wind Speed

See the full Seongnam climate overview or explore weather in South Korea.