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 51–65°F, 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 72–83°F, 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 60–80°F, 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 44–49°F, 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. 63.7°F / Annual rainfall: approx. 1794 mm / Summer humidity: 70%–80% / Rainiest month: May
Koyasan monthly average temperature and precipitation
Month
Air temperature (°F)
Precipitation (mm)
January
45°F
63.9
February
45°F
59.2
March
51.1°F
113.6
April
59.7°F
163.5
May
65.5°F
313.2
June
72.7°F
285.1
July
81.3°F
200.3
August
83.7°F
130.6
September
80.6°F
161.5
October
68.9°F
141
November
60.3°F
101.2
December
49.6°F
61.5
Koyasan weather for the next seven days
5/11
Monday
Sunny
73.3°F/47.8°F
5/12
Tuesday
Patchy rain nearby
75.2°F/48.9°F
5/13
Wednesday
Partly Cloudy
72.9°F/48.3°F
5/14
Thursday
Patchy rain nearby
76.6°F/54°F
5/15
Friday
Patchy rain nearby
76.3°F/51.7°F
5/16
Saturday
Sunny
80.4°F/53.9°F
5/17
Sunday
Partly Cloudy
83°F/56°F
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