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Niihama Weather by Month
Average temperatures, rainfall and humidity for Niihama, Japan, month by month, built from OpenWeather's historical records. Use it to see what a typical Niihama month looks like before you travel — then check the live Niihama forecast for the days ahead.
Warmest month
August
31°C average high
Coolest month
February
3°C average low
Wettest month
June
192 mm of rain
Driest month
January
51 mm of rain
Average temperature and rainfall in Niihama 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 | 9°C | 3°C | -10°C / 21°C | 51 mm | 71% | 14 km/h |
| February | 10°C | 3°C | -12°C / 20°C | 115 mm | 70% | 14 km/h |
| March | 13°C | 7°C | -7°C / 24°C | 112 mm | 70% | 13 km/h |
| April | 18°C | 11°C | 0°C / 26°C | 140 mm | 72% | 11 km/h |
| May | 22°C | 15°C | 1°C / 31°C | 112 mm | 74% | 9 km/h |
| June | 25°C | 20°C | 11°C / 33°C | 192 mm | 83% | 8 km/h |
| July | 29°C | 24°C | 17°C / 34°C | 143 mm | 83% | 8 km/h |
| August | 31°C | 25°C | 16°C / 36°C | 150 mm | 80% | 8 km/h |
| September | 27°C | 22°C | 9°C / 34°C | 142 mm | 80% | 10 km/h |
| October | 22°C | 16°C | -1°C / 32°C | 92 mm | 75% | 12 km/h |
| November | 17°C | 10°C | -4°C / 25°C | 65 mm | 73% | 12 km/h |
| December | 11°C | 5°C | -11°C / 21°C | 52 mm | 72% | 14 km/h |
Best time to visit Niihama
The most comfortable time to visit Niihama is generally May and September to 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 1365 mm a year.
Travellers who prefer heat should aim for August, when highs average 31°C. June is the month to avoid if rain would spoil your plans — it averages 192 mm, roughly 4× the rainfall of January.
Source: OpenWeather historical and statistical weather data. Values are long-term averages, not a forecast — see the Niihama forecast for what is happening now.