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Koyasan weather by month

Koyasan runs from about 1°C in January to 24°C in August, with June the wettest month at 331 mm.

warmest month

August

24°C

coolest month

January

1°C

wettest month

June

331 mm

worst air month

February

19 µg/m³

The whole year, month by month.

Monthly climate normals for Koyasan
MonthAvg tempRainSunPM2.5
January1°C74 mm203 h13
February3°C151 mm170 h19
March4°C253 mm234 h18
April12°C162 mm199 h18
May14°C320 mm254 h13
June18°C331 mm248 h15
July24°C155 mm318 h14
August24°C173 mm328 h16
September22°C125 mm291 h13
October16°C207 mm212 h12
November9°C168 mm222 h18
December1°C38 mm244 h15

About 2,923 hours of sun a year. Roughly 211 rainy days a year.

These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.