Climate Insights for Sejong

The climate in Sejong is temperate. The average annual temperature is 14°C and approximately 1171mm of precipitation falls per year. July is the wettest month, receiving around 270mm of rainfall. Sejong is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: August, July, June. The coldest months are January, December, February, when temperatures can drop to -5°C. Light snow can occur between January and December.

Sejong has a wide annual temperature range, spanning 36°C from the coldest to warmest months. The warmest month is August, when average highs reach 31°C and the mean temperature sits around 27°C. The coldest month is January, when overnight lows fall to -5°C and the daily average is -1°C. On average, daily temperatures fluctuate by about 10°C between overnight lows and afternoon highs. The sharpest temperature change occurs between September and October, with a 7°C shift in average temperatures.

Sejong is a moderately rainy area, receiving approximately 1171mm of precipitation annually, which averages out to around 98mm per month. The wettest month is July, averaging 270mm of rainfall. August and September also tend to see above-average precipitation. The driest month is January, with just 22mm. That's 248mm less than July, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic. Light snowfall can occur between January and December, totalling around 17cm annually. February is the snowiest month with approximately 5cm.

Sejong is relatively calm, with an average annual wind speed of 9km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is February, averaging 10km/h, though still comfortable for most outdoor activities. The calmest conditions occur in August, with average winds dropping to 8km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 2km/h between the calmest and windiest months.

It is currently summer in Sejong, which began on June 21, 2026. Sejong is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in August at around 31°C, while the coldest stretch bottoms out in January near -5°C. Autumn is next, beginning on September 23, 2026 (3 days from now).

The best time to visit Sejong is during May, when the weather is most comfortable for travellers. During these months, average temperatures hover around 19°C with modest rainfall averaging 88mm per month. By contrast, August can be uncomfortably hot with highs reaching 31°C, while January is the coldest period with lows dropping to -5°C. Despite being the best months overall, some rain is still likely. Pack a waterproof layer and plan a mix of indoor and outdoor activities.

The table below shows monthly climate averages for Sejong based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.