Climate Overview
The climate in Oyama is temperate. The average annual temperature is 12°C and approximately 2079mm of precipitation falls per year. Oyama receives a notable amount of rainfall throughout the year, including during its driest month. Oyama 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 -3°C. Snowfall occurs from January to December, with around 136cm accumulating over the season.
Temperature
Temperatures in Oyama vary considerably across the year, with a 31°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 24°C. The coldest month is January, when overnight lows fall to -3°C and the daily average is 1°C. Daily temperature variation is modest, with an average difference of 8°C between highs and lows. The sharpest temperature change occurs between September and October, with a 6°C shift in average temperatures.
Precipitation
Oyama is a very wet location, receiving approximately 2079mm of precipitation annually, which averages out to around 173mm per month. The wettest month is October, averaging 329mm of rainfall. July and September also tend to see above-average precipitation. The driest month is December, with just 64mm. That's 265mm less than October, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic. Snowfall is a regular feature from January to December, with around 136cm accumulating over the season. March typically sees the most snow at around 47cm.
Wind
Oyama is relatively calm, with an average annual wind speed of 1km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is April, averaging 2km/h, though still comfortable for most outdoor activities. The calmest conditions occur in November, with average winds dropping to 1km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 1km/h between the calmest and windiest months.
Seasons
92 days until Autumn
It is currently summer in Oyama, which began on June 21, 2026. Oyama 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 -3°C. Autumn is next, beginning on September 23, 2026 — 92 days from now.
Spring
Temperatures range from 1 to 21°C. Rainfall is heavy, totalling around 474mm across the season with a monthly average of 158mm. Winds are generally light, averaging 2km/h. An umbrella or waterproof jacket is advisable as spring showers are frequent.
Summer
Temperatures range from 15 to 28°C. Rainfall is heavy, totalling around 685mm across the season with a monthly average of 228mm. Winds are generally light, averaging 1km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.
Autumn
Temperatures range from 5 to 24°C. Rainfall is heavy, totalling around 685mm across the season with a monthly average of 228mm. Expect around 6cm of snow accumulation during this period. Winds are generally light, averaging 1km/h. A waterproof jacket and sturdy footwear are recommended as rain becomes more frequent.
Winter
Temperatures range from -3 to 9°C. Precipitation is moderate at around 234mm for the season, averaging 78mm per month. Expect around 76cm of snow accumulation during this period. Winds are generally light, averaging 2km/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 Oyama 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.