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Koshigaya Weather by Month
Average temperatures, rainfall and humidity for Koshigaya, Japan, month by month, built from OpenWeather’s historical records. Use it to see what a typical Koshigaya month looks like before you travel — then check the live Koshigaya forecast for the days ahead.
Warmest month
August
32°C average high
Coolest month
January
2°C average low
Wettest month
June
158 mm of rain
Driest month
January
27 mm of rain
Average temperature and rainfall in Koshigaya by month
Averages of the daily highs and lows recorded in each month, with total rainfall, mean humidity and mean wind speed.
| Month | Avg high | Avg low | Record low / high | Rainfall | Humidity | Wind |
|---|---|---|---|---|---|---|
| January | 10°C | 2°C | -9°C / 19°C | 27 mm | 56% | 15 km/h |
| February | 11°C | 3°C | -5°C / 23°C | 42 mm | 58% | 16 km/h |
| March | 15°C | 7°C | -3°C / 28°C | 83 mm | 62% | 16 km/h |
| April | 19°C | 12°C | 1°C / 29°C | 107 mm | 66% | 17 km/h |
| May | 24°C | 17°C | 7°C / 34°C | 109 mm | 70% | 16 km/h |
| June | 27°C | 20°C | 13°C / 38°C | 158 mm | 74% | 14 km/h |
| July | 31°C | 24°C | 18°C / 39°C | 116 mm | 75% | 14 km/h |
| August | 32°C | 26°C | 17°C / 40°C | 129 mm | 72% | 15 km/h |
| September | 28°C | 22°C | 13°C / 37°C | 138 mm | 75% | 14 km/h |
| October | 22°C | 16°C | 5°C / 32°C | 124 mm | 72% | 14 km/h |
| November | 17°C | 10°C | -1°C / 27°C | 61 mm | 64% | 12 km/h |
| December | 12°C | 4°C | -6°C / 23°C | 36 mm | 57% | 14 km/h |
Best time to visit Koshigaya
The most comfortable time to visit Koshigaya is generally April to May and October, balancing mild daytime temperatures against the driest stretch of the year. The city has strongly marked seasons and rain concentrates around June, totalling about 1,130 mm a year.
Travellers who prefer heat should aim for August, when highs average 32°C. June is the month to avoid if rain would spoil your plans — it averages 158 mm, roughly 6× the rainfall of the driest month (January).
Source: OpenWeather historical and statistical weather data. Values are long-term averages, not a forecast — see the Koshigaya forecast for what is happening now.