Climate Overview
The climate in Kumamoto is temperate. The average annual temperature is 18°C and approximately 2249mm of precipitation falls per year. Kumamoto receives a notable amount of rainfall throughout the year, including during its driest month. Kumamoto 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 6°C.
Temperature
Temperatures in Kumamoto vary considerably across the year, with a 25°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 6°C and an average of 8°C. Daily temperature variation is modest, with an average difference of 5°C between highs and lows. The sharpest temperature change occurs between November and December, with a 6°C shift in average temperatures.
Precipitation
Kumamoto is a very wet location, receiving approximately 2249mm of precipitation annually, which averages out to around 187mm per month. The wettest month is June, averaging 432mm of rainfall. July and May also tend to see above-average precipitation. The driest month is December, with just 87mm. That's 345mm less than June, the wettest month. Precipitation varies noticeably between seasons, with the first half (January to June) of the year generally seeing more rainfall.
Wind
Kumamoto is mildly breezy, with an average annual wind speed of 15km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is February, averaging 16km/h, though still comfortable for most outdoor activities. The calmest conditions occur in May, with average winds dropping to 14km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 2km/h between the calmest and windiest months.
Seasons
89 days until Summer
It is currently spring in Kumamoto, which began on March 20, 2026. Kumamoto 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 6°C. Summer is next, beginning on June 21, 2026 — 89 days from now.
Spring
Temperatures range from 9 to 23°C. Rainfall is heavy, totalling around 556mm across the season with a monthly average of 185mm. Winds are generally light, averaging 15km/h. An umbrella or waterproof jacket is advisable as spring showers are frequent.
Summer
Temperatures range from 21 to 31°C. Rainfall is heavy, totalling around 990mm across the season with a monthly average of 330mm. Winds are generally light, averaging 14km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.
Autumn
Temperatures range from 13 to 28°C. Rainfall is heavy, totalling around 411mm across the season with a monthly average of 137mm. Winds are generally light, averaging 14km/h. A waterproof jacket and sturdy footwear are recommended as rain becomes more frequent.
Winter
Temperatures range from 6 to 12°C. Precipitation is moderate at around 292mm for the season, averaging 97mm per month. Winds are moderate at around 16km/h. A light jacket or sweater is usually sufficient, though cooler evenings may call for an extra layer.
Monthly Climate Data
The table below shows monthly climate averages for Kumamoto 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.
