Everyone who was supposed to go did so, and our tour guide, Li Yan, was very responsible. Besides the basic assistance, he provided comprehensive commentary in both audio and video, never skipping a single point just because there were only two or three people who needed Chinese-language explanations. He would repeat the same things to us again. Li Yan was fantastic! Li Yan, who has lived in Japan for 16 years 😂 (Also, the gentleman from another car traveling with us that day noticed we were waiting for our car and couldn't find him, so he immediately came over with a sign to check on us).
Anonymous User
Family
Koyasan Weather, Climate and Best Time to Visit
Data source:Meteostat Update date:2025-09
Koyasan year round climate
Spring (March–May): Average 10.6–18.6°C, mild and comfortable climate, but with relatively high rainfall, especially in May. Common activities: Visiting Koyasan temples, hiking (be aware of changing weather conditions). Recommended clothing: Light jacket, long-sleeved shirt, rain gear.
Summer (June–August): Average 22.6–28.7°C, hot and humid, with occasional showers. Common activities: Visiting temples, experiencing local culture, escaping the heat in the mountains. Recommended clothing: Breathable and sweat-wicking clothing, sun hat, rain gear.
Autumn (September–November): Average 15.7–27.0°C, comfortable and pleasant climate, with reduced rainfall. Common activities: Autumn leaves viewing (in some areas), visiting temples, hiking. Recommended clothing: Light jacket, long-sleeved shirt.
Winter (December–February): Average 7.2–9.8°C, cold and dry, with little rain. Common activities: Visiting temples, experiencing onsen (in nearby areas). Recommended clothing: Warm jacket, sweater, scarf, gloves.
Koyasan climatological average
Annual average temperature: approx. 17.6°C / Annual rainfall: approx. 1794 mm / Summer humidity: 70%–80% / Rainiest month: May
Koyasan monthly average temperature and precipitation
Month
Air temperature (°C)
Precipitation (mm)
January
7.2°C
63.9
February
7.2°C
59.2
March
10.6°C
113.6
April
15.4°C
163.5
May
18.6°C
313.2
June
22.6°C
285.1
July
27.4°C
200.3
August
28.7°C
130.6
September
27°C
161.5
October
20.5°C
141
November
15.7°C
101.2
December
9.8°C
61.5
Koyasan weather for the next seven days
5/11
Monday
Patchy rain nearby
23°C/9.1°C
5/12
Tuesday
Patchy rain nearby
21.8°C/10.3°C
5/13
Wednesday
Partly Cloudy
22.8°C/11.4°C
5/14
Thursday
Patchy rain nearby
24°C/10.9°C
5/15
Friday
Patchy rain nearby
24.6°C/11.1°C
5/16
Saturday
Patchy rain nearby
24.9°C/12.7°C
5/17
Sunday
Sunny
26.3°C/12.9°C
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