South Korea Weather in September 2025: Travel Tips for First-Timers

September is a shoulder month marking the onset of autumn and the end of summer in South Korea, and one of the best months to visit the country. It's cool and comfortable, with temperatures ranging from highs of 26°C (79°F) to lows of 15°C (59°F) over the course of the month.

Except for the three days of the mid-autumn festival of Chuseok, it is, overall, not so crowded in South Korea during September. You can hang out at the beach and visit your favorite tourist attractions without having to worry about large hordes of tourists around, whilst also paying reasonable prices for accommodation and transportation. Schools resuming from their summer breaks have contributed to this temporary lull in tourism, and the country will experience an influx of tourists once again in October.

The weather can change quickly in South Korea in September. It can go from hot and dry to cool and windy in a matter of minutes. As such, it's good to carry a scarf or a light jacket with you when possible. It will definitely get chillier towards the end of the month.

To get an in-depth understanding of what to expect insofar as weather conditions are concerned during September, keep reading below.

South Korea Weather in September: Overview

• Average temperature range: 15°C – 26°C (59°F – 79°F)
• Rainfall: 124 mm (5 inches) in Seoul; 166 mm (6.5 inches) in Busan; 174 mm (7 inches) in Jeju.
• Rainy days: 7 in Seoul; 10 in Busan; 7 in Jeju.

The beginning of fall and end of summer means the oppressive heat and humidity of the previous months is finally behind us. It's cool, comfortable, and downright beautiful this time of year in South Korea.

The average maximum daytime temperatures hover around the 25°C (77°F) mark in Seoul, 26°C (79°F) in Busan, and 25°C (77°F) in Jeju Island. The average minimums, usually recorded at nighttime, hover around the 16°C (61°F) mark in Seoul, 19°C (66°F) in Busan, and 19°C (66°F) in Jeju Island.

The gorgeous September weather makes it one of the best months to visit South Korea, especially if you're looking to spend time outdoors.

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Weather of South Korea's Major Cities in September

Best Places to Visit in South Korea in September

1. Seoul

Come September, the capital benefits from some much-needed relief from the warmer summer temperatures. It's a great time to head out and visit Gyeongbokgung Palace, Changdeokgung Palace, Namsan Hanok Village, and the DMZ or Demilitarized Zone shared between North and South Korea.

2. Busan

Much cooler than landlocked Seoul, the seaside city of Busan offers visitors a mixture of outdoor and indoor activities to choose from. Although cool, the city also benefits from endless hours of sunshine during September which could be enjoyed sunbathing at one of the city's splendid beaches or touring important cultural sites like the awe-inspiring Haedong Yonggungsa Temple.

3. Jeju Island

There are few places in the Korean peninsula that offer as many outdoor activities as does Jeju Island. From relaxing on the beach and taking dips in the island's temperate waters to horse riding and exploring UNESCO sites such as Manjang Cave, if there's a place in South Korea that is your one-stop paradise of adventure, it's Jeju Island.

September Crowds and Costs

Not only is the weather gorgeous during September, but it's also an ideal month to visit South Korea given the temporary lull in tourism experienced during August and October. Korean schools have resumed from their summer breaks, meaning you're likely to encounter far fewer crowds of tourists when exploring your favorite tourist attractions. This also means fewer queues to wait in and the added advantage of getting to explore in relative peace and quiet.

Prices are reasonable insofar as accommodation and transportation are concerned, and if you book in advance, you're likely to find good deals on airfare.

September Events in South Korea

Chuseok: Chuseok, also known as Hangawi, is the Korean mid-autumn harvest festival. The exact date of observance depends on the day's placement in the lunar calendar but like other harvest festivals observed around the world, Chuseok falls around the autumn equinox.

As one of the biggest and most important festivals in both Koreas, you can think of Chuseok as the Korean Thanksgiving. Everyone is either visiting family members back home or taking trips to their favorite destinations. Meals are shared and families express gratitude for their ancestors before playing traditional games and watching folk performances.

Muju Firefly Festival: this nine-day affair takes place with much fanfare in Muju, a natural habitat for fireflies and marsh snails, every autumn. Since fireflies are most active at the beginning of September from the 7th to the 15th of the month. The festival is designed to help conserve and raise awareness about fireflies.

Taste of Seoul: Taste of Seoul is the only food festival in Seoul and takes place over the course of a week. Organized by the city as a celebration of the capital's diverse culinary nature, chefs from some of the best eateries in Seoul, South Korea, and even the world, come together to dish up flavorful items for foodies and culinary enthusiasts. You'll be talking about the food you get to try at this festival for years to come!

What to Wear in South Korea in September

As a shoulder month, September in South Korea is characterized by rapidly changing weather conditions. It can go from hot and dry to cool and windy in a matter of minutes, so it's best to stay prepared by carrying a scarf or light jacket with you when possible.

It's warmer during the first half of September and begins to cool towards the second. So, while it's suitable to walk around in shorts and a linen top during the first part of September, those won't suffice for when temperatures drop, and long-sleeved shirts and sweaters are needed.

A comprehensive packing list for September in South Korea ought to include linen shorts and shirts, jeans, light weight jackets and sweaters, windbreakers, scarves, and leggings.

Do also carry your swimwear as the waters in Jeju Island are still warm enough for a dip.

Explore South Korea with Global Highlights

Planning a trip to South Korea? Look no further! Our team of travel experts at Global Highlights are here to ensure you have the time of your life when visiting splendid South Korea. With thousands of planned tours under our belt, it's safe to say our specialty is curating trips that go above and beyond in remaining memorable and meaningful for you and your loved ones. We'll keep everything from weather conditions to special interests in mind, so that you can just relax and enjoy the journey!