Karuizawa Weather & Climate: Best Time to Visit

The climate in Karuizawa is known for significant temperature differences throughout the year, making the weather dynamic. Typically, average maximum daytime temperatures range from a comfortable 28°C (82°F) in August to a chilly 4°C (39°F) in the coolest month, January.

Nights vary from 19°C (66°F) in August to around -5°C (23°F) during the colder months.

Check out our detailed temperature page for more information.

Temperature ranges by month

Karuizawa has a notably wet climate with abundant precipitation, recording 1785 mm (70 in) of rain/snowfall per year. The climate in Karuizawa shows significant variation throughout the year. Expect heavy rainfall in July, the wettest month, with an average of 255 mm (10 in) of precipitation over 23 rainy days.

In contrast, the driest month December offers drier and sunnier days, with around 63 mm (2.5 in) of snow/rainfall over 15 snowy/rainy days. For more details, please visit our Karuizawa Precipitation page.

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

The average number of days each month with precipitation

Karuizawa offers a pleasant mix of sunny and slightly overcast days. The difference in sunshine hours between May (7.0 hours daily) and January (4.3 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

The relative humidity is high throughout the year in Karuizawa.

The city experiences its highest humidity in January, reaching 78%. In April, the humidity drops to its lowest level at 61%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year