Koyasan Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Koyasan.
Climate overview of Koyasan
The climate in Koyasan, Wakayama, Japan, is marked by large temperature swings across the seasons, ranging from 32°C (90°F) in August to 8°C (46°F) in January.
The city has a wet climate, receiving around 1984 mm (78 in) of rain/snowfall per year. June is the wettest month. Sunshine peaks in August, when the city sees around 7.6 hours of sunshine per day.
Koyasan Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Koyasan — and find the best time to visit.
Monthly Temperature in Koyasan
In Koyasan, temperatures differ significantly between summer and winter months. On average, daytime temperatures range from a very warm 32°C (90°F) in August to a chilly 8°C (46°F) in January.
Nighttime temperatures range from 23°C (73°F) in August to -1°C (30°F) in January.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Koyasan
Koyasan experiences significant rain/snowfall throughout the year, averaging 1984 mm (78 in) of precipitation annually. The seasons in Koyasan bring significant changes in precipitation. The wettest month, June, receives heavy rainfall, with an average of 299 mm (12 in) of precipitation. This rainfall is distributed across 19 rainy days.
In contrast, the driest month, December, experiences much less rainfall, totaling 91 mm (3.6 in) over 14 rainy days. These distinct seasonal differences provide diverse experiences throughout the year. For more details, please visit our Koyasan Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in Koyasan
In Koyasan, summer days are longer and more sunny, with daily sunshine hours peaking at 7.6 hours in August. As the darker season arrives, the brightness of the sun becomes less. February sees a soft sun for only 4.5 hours per average day.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Humidity in Koyasan by Month
The relative humidity is high throughout the year in Koyasan.
The city experiences its highest humidity in July, reaching 76%. In March, the humidity drops to its lowest level at 62%. What does this mean? Read our detailed page on humidity levels for further details.
Relative humidity over the year
Best Time to Visit Koyasan
Be prepared for heavier rainfall during May, June, July, August, September and October, the wettest period of the year. Seeking the perfect travel destination for this year? We've created a tool that suggests locations matching your desired weather. Let our weather planner guide your travel decisions.
Frequently asked questions about the climate in Koyasan
What is the best time to visit Koyasan?
May typically offers the most optimal weather in Koyasan. In contrast, January, February, March, June and July tend to have less optimal conditions.
What temperatures can I expect in Koyasan?
Daytime highs range from 8°C (46°F) in January to 32°C (90°F) in August. Nighttime lows range from -1°C (30°F) to 23°C (73°F). Temperatures vary considerably through the year.
How much rain does Koyasan get?
Annual rainfall is around 1984 mm (78 in). June is the wettest month with 299 mm (12 in), while December is the driest with 91 mm (3.6 in).
How sunny is Koyasan?
Koyasan receives around 2,027 hours of sunshine per year. August is the sunniest month with 228 hours, while February is the cloudiest with just 134 hours. Overall, Koyasan enjoys abundant sunshine.
Koyasan 3-Day Forecast
Koyasan 3-Day Forecast
Koyasan on the map
Koyasan is highlighted — select any city to see its climate.
Popular this month
Where to go in July — average daytime high across popular destinations.
Osaka
32°C (90°F) Tokyo30°C (86°F) Naha
30°C (86°F) Kyoto31°C (88°F) Hakone28°C (82°F) Hakuba26°C (79°F) Sapporo24°C (75°F) Niseko24°C (75°F) 
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