Climate Insights for Jōetsu

The climate in Jōetsu is temperate. The average annual temperature is 15°C and approximately 2028mm of precipitation falls per year. Jōetsu receives a notable amount of rainfall throughout the year, including during its driest month. Jōetsu is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: August, July, September. The coldest months are January, February, December, when temperatures can drop to 2°C. Snowfall occurs from January to December, with around 184cm accumulating over the season.

Temperatures in Jōetsu vary considerably across the year, with a 29°C difference between the coldest and warmest months. The warmest month is August, when average highs reach 31°C and the mean temperature sits around 28°C. January is the coolest month, with minimum temperatures around 2°C and an average of 4°C. Daily temperature variation is modest, with an average difference of 6°C between highs and lows. The sharpest temperature change occurs between September and October, with a 6°C shift in average temperatures.

Jōetsu is a very wet location, receiving approximately 2028mm of precipitation annually, which averages out to around 169mm per month. The wettest month is December, averaging 283mm of rainfall. January and July also tend to see above-average precipitation. The driest month is May, with just 104mm. That's 179mm less than December, the wettest month. Precipitation varies noticeably between seasons, with the second half (July to December) of the year generally seeing more rainfall. Snowfall is a regular feature from January to December, with around 184cm accumulating over the season. January typically sees the most snow at around 83cm.

Jōetsu is mildly breezy, with an average annual wind speed of 19km/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 25km/h, noticeable enough to affect lighter outdoor activities. The calmest conditions occur in July, with average winds dropping to 14km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 11km/h gap 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 24km/h in winter, 19km/h in spring, 15km/h in summer, 18km/h in autumn.

It is currently spring in Jōetsu, which began on March 20, 2026. Jōetsu 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 2°C. Summer is next, beginning on June 21, 2026 — 89 days from now.

The table below shows monthly climate averages for Jōetsu 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.