Climate Insights for Hachijō

The climate in Hachijō is warm and mild. The average annual temperature is 20°C and approximately 2355mm of precipitation falls per year. Hachijō receives a notable amount of rainfall throughout the year, including during its driest month. Hachijō is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: August, September, July. The coldest months are February, January, March, when temperatures can drop to 12°C.

Hachijō sees moderate temperature variation throughout the year, ranging from 12°C to 28°C. The warmest month is August, when average highs reach 28°C and the mean temperature sits around 28°C. February is the coolest month, with minimum temperatures around 12°C and an average of 13°C. Daily temperature variation is modest, with an average difference of 2°C between highs and lows. The sharpest temperature change occurs between November and December, with a 4°C shift in average temperatures.

Hachijō is a very wet location, receiving approximately 2355mm of precipitation annually, which averages out to around 196mm per month. The wettest month is September, averaging 324mm of rainfall. June and October also tend to see above-average precipitation. The driest month is August, with just 124mm. That's 199mm less than September, the wettest month. Precipitation varies noticeably between seasons, with the second half (July to December) of the year generally seeing more rainfall.

Hachijō is relatively calm, with an average annual wind speed of 8km/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 10km/h, though still comfortable for most outdoor activities. The calmest conditions occur in July, with average winds dropping to 6km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 4km/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 10km/h in winter, 8km/h in spring, 7km/h in summer, 8km/h in autumn.

It is currently summer in Hachijō, which began on June 21, 2026. Hachijō 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 February near 12°C. Autumn is next, beginning on September 23, 2026 — 91 days from now.

The table below shows monthly climate averages for Hachijō 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.