Climate Overview
The climate in Ōyama is warm and mild. The average annual temperature is 18°C and approximately 2388mm of precipitation falls per year. Ōyama receives a notable amount of rainfall throughout the year, including during its driest month. Ōyama 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 8°C.
Temperature
Ōyama sees moderate temperature variation throughout the year, ranging from 8°C to 28°C. The warmest month is August, when average highs reach 28°C and the mean temperature sits around 27°C. January is the coolest month, with minimum temperatures around 8°C and an average of 10°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 5°C shift in average temperatures.
Precipitation
Ōyama is a very wet location, receiving approximately 2388mm of precipitation annually, which averages out to around 199mm per month. The wettest month is June, averaging 357mm of rainfall. September and July also tend to see above-average precipitation. The driest month is January, with just 84mm. That's 273mm less than June, the wettest month. Precipitation varies noticeably between seasons, with the second half (July to December) of the year generally seeing more rainfall.
Wind
Ōyama is very windy, with an average annual wind speed of 35km/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 43km/h, which can feel quite blustery and may affect outdoor activities. The calmest conditions occur in July, with average winds dropping to 28km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 15km/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 42km/h in winter, 34km/h in spring, 28km/h in summer, 34km/h in autumn.
Seasons
88 days until Summer
It is currently spring in Ōyama, which began on March 20, 2026. Ōyama 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 8°C. Summer is next, beginning on June 21, 2026 — 88 days from now.
Spring
Temperatures range from 11 to 20°C. Rainfall is heavy, totalling around 601mm across the season with a monthly average of 200mm. Winds are strong, averaging 34km/h. An umbrella or waterproof jacket is advisable as spring showers are frequent.
Summer
Temperatures range from 21 to 28°C. Rainfall is heavy, totalling around 805mm across the season with a monthly average of 268mm. Winds are strong, averaging 28km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.
Autumn
Temperatures range from 16 to 26°C. Rainfall is heavy, totalling around 698mm across the season with a monthly average of 233mm. Winds are strong, averaging 34km/h. A waterproof jacket and sturdy footwear are recommended as rain becomes more frequent.
Winter
Temperatures range from 8 to 14°C. Precipitation is moderate at around 283mm for the season, averaging 94mm per month. Winds are strong, averaging 42km/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 Ōyama 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.