Climate Insights for Ulsan

The climate in Ulsan is temperate. The average annual temperature is 15°C and approximately 1315mm of precipitation falls per year. Ulsan receives a notable amount of rainfall throughout the year, including during its driest month. Ulsan 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 -1°C.

Temperatures in Ulsan vary considerably across the year, with a 31°C difference between the coldest and warmest months. The warmest month is August, when average highs reach 30°C and the mean temperature sits around 27°C. The coldest month is January, when overnight lows fall to -1°C and the daily average is 3°C. Daily temperature variation is modest, with an average difference of 8°C between highs and lows. The sharpest temperature change occurs between November and December, with a 7°C shift in average temperatures.

Ulsan is a fairly wet location, receiving approximately 1315mm of precipitation annually, which averages out to around 110mm per month. The wettest month is September, averaging 234mm of rainfall. August and July also tend to see above-average precipitation. The driest month is December, with just 31mm. That's 203mm less than September, 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.

Ulsan is mildly breezy, with an average annual wind speed of 18km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is January, averaging 19km/h, though still comfortable for most outdoor activities. The calmest conditions occur in June, with average winds dropping to 16km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 3km/h between the calmest and windiest months. Wind tends to be stronger during winter months, driven by seasonal pressure systems. The seasonal averages break down to 19km/h in winter, 18km/h in spring, 17km/h in summer, 17km/h in autumn.

It is currently spring in Ulsan, which began on March 20, 2026. Ulsan 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 30°C, while the coldest stretch bottoms out in January near -1°C. Summer is next, beginning on June 21, 2026 — 89 days from now.

The best time to visit Ulsan is during May and October, when the weather is most comfortable for travellers. During these months, average temperatures hover around 18°C with modest rainfall averaging 91mm per month. By contrast, August can be uncomfortably hot with highs reaching 30°C, while January is the coldest period with lows dropping to -1°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 Ulsan 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. 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.