Climate Overview
The climate in Itoigawa is temperate. The average annual temperature is 12°C and approximately 2947mm of precipitation falls per year. Itoigawa receives a notable amount of rainfall throughout the year, including during its driest month. Itoigawa 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. Itoigawa experiences heavy snowfall, typically from January through December.
Temperature
Temperatures in Itoigawa vary considerably across the year, with a 30°C difference between the coldest and warmest months. The warmest month is August, when average highs reach 28°C and the mean temperature sits around 25°C. The coldest month is January, when overnight lows fall to -2°C and the daily average is 0°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 7°C shift in average temperatures.
Precipitation
Itoigawa is a very wet location, receiving approximately 2947mm of precipitation annually, which averages out to around 246mm per month. The wettest month is July, averaging 345mm of rainfall. January and December also tend to see above-average precipitation. The driest month is May, with just 160mm. That's 185mm less than July, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around. Itoigawa receives heavy snowfall, accumulating around 510cm annually from January through December. The snowiest month is January, with approximately 180cm. Winter travel should account for significant snow cover.
Wind
Itoigawa is relatively calm, with an average annual wind speed of 12km/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 15km/h, though still comfortable for most outdoor activities. The calmest conditions occur in July, with average winds dropping to 9km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 6km/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 14km/h in winter, 12km/h in spring, 9km/h in summer, 12km/h in autumn.
Seasons
89 days until Summer
It is currently spring in Itoigawa, which began on March 20, 2026. Itoigawa 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 28°C, while the coldest stretch bottoms out in January near -2°C. Summer is next, beginning on June 21, 2026 — 89 days from now.
Spring
Temperatures range from 1 to 20°C. Rainfall is heavy, totalling around 496mm across the season with a monthly average of 165mm. Winds are generally light, averaging 12km/h. An umbrella or waterproof jacket is advisable as spring showers are frequent.
Summer
Temperatures range from 16 to 28°C. Rainfall is heavy, totalling around 837mm across the season with a monthly average of 279mm. Winds are generally light, averaging 9km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.
Autumn
Temperatures range from 6 to 24°C. Rainfall is heavy, totalling around 736mm across the season with a monthly average of 245mm. Expect around 18cm of snow accumulation during this period. Winds are generally light, averaging 12km/h. A waterproof jacket and sturdy footwear are recommended as rain becomes more frequent.
Winter
Temperatures range from -2 to 5°C. Rainfall is heavy, totalling around 879mm across the season with a monthly average of 293mm. Expect around 429cm of snow accumulation during this period. Winds are generally light, averaging 14km/h. Warm winter clothing and waterproof boots are a must, and travel may be affected by snow.
Monthly Climate Data
The table below shows monthly climate averages for Itoigawa 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.
