Osan Weather & Climate: Best Time to Visit

The climate in Osan is known for significant temperature differences throughout the year, making the weather dynamic. Typically, average maximum daytime temperatures range from a very warm 31°C (88°F) in August to a chilly 4°C (39°F) in the coolest month, January.

Nights vary from 23°C (73°F) in August to around -6°C (21°F) during the colder months.

Check out our detailed temperature page for more information.

Temperature ranges by month

Osan has a notably wet climate with abundant precipitation, recording 1187 mm (47 in) of rain/snowfall per year. The climate in Osan shows significant variation throughout the year. Expect heavy rainfall in July, the wettest month, with an average of 281 mm (11 in) of precipitation over 16 rainy days.

In contrast, the driest month January offers drier and sunnier days, with around 24 mm (0.9 in) of snow/rainfall over 8 snowy/rainy days. For more details, please visit our Osan Precipitation page.

The mean monthly precipitation over the year, including rain, hail, and snow

The average number of days each month with precipitation

Osan offers a pleasant mix of sunny and slightly overcast days. The difference in sunshine hours between May (8.3 hours daily) and December (5.3 hours daily) provides a bit of variety for visitors and residents.

Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Daily hours of sunshine

Daily percentage of sunshine

The relative humidity is high throughout the year in Osan.

The city experiences its highest humidity in July, reaching 78%. In April, the humidity drops to its lowest level at 62%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year