Climate averages 1991–2020
Niihama weather
in May.
A warm, wet month: the 5th warmest and the 8th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a warm month in Niihama: daytime highs average 22.8°C and nights cool to about 15.1°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 158 mm of rain on roughly 11 days, which makes May a wet month (the 8th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 13 h 54 min on an average May day.
The nearest other city in this atlas is Saijō (12 km away). In May its highs average 23.8°C, 1.0°C warmer than Niihama, with 158 mm of rain.
Among the 303 cities listed in Japan, Niihama ranks joint 45th of 303 for the warmest May highs and joint 213th of 303 for the driest May (rainfall, lowest first). The mean May high of those 303 cities is 21.3°C; Niihama is 1.4°C warmer than that mean.
From May to June, average highs rise by 3.0°C to 25.8°C, and monthly rainfall rises from 158 mm to 249 mm.
The annual picture
May in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Niihama climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 9.0°C3.3°C | 3.3°C | 78 | 13.5 | 10.210 h |
| February | 10.1°C3.3°C | 3.3°C | 86 | 12.3 | 10.911 h |
| March | 13.6°C5.8°C | 5.8°C | 122 | 13.4 | 12.012 h |
| April | 18.5°C10.4°C | 10.4°C | 134 | 11.6 | 13.013 h |
| May, selected | 22.8°C15.1°C | 15.1°C | 158 | 11.2 | 13.914 h |
| June | 25.8°C19.5°C | 19.5°C | 249 | 15.1 | 14.414 h |
| July | 29.5°C23.9°C | 23.9°C | 228 | 15.6 | 14.214 h |
| August | 30.6°C24.8°C | 24.8°C | 151 | 13.8 | 13.413 h |
| September | 27.1°C21.4°C | 21.4°C | 216 | 14.1 | 12.412 h |
| October | 21.9°C15.7°C | 15.7°C | 166 | 11.0 | 11.411 h |
| November | 16.6°C10.2°C | 10.2°C | 90 | 9.9 | 10.410 h |
| December | 11.4°C5.5°C | 5.5°C | 90 | 12.8 | 9.910 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
May in nearby cities
- Saijō in MayJapan · 12 kmHigh 23.8°C · Low 15.6°C · 158 mm rain
- Shikokuchūō in MayJapan · 23 kmHigh 23.0°C · Low 15.0°C · 170 mm rain
- Imabari in MayJapan · 31 kmHigh 21.8°C · Low 15.6°C · 156 mm rain
- Shinagawa in MayJapan · 45 kmHigh 22.5°C · Low 13.8°C · 174 mm rain
- Kochi in MayJapan · 50 kmHigh 22.8°C · Low 14.1°C · 242 mm rain
- Matsuyama in MayJapan · 52 kmHigh 23.1°C · Low 15.2°C · 154 mm rain
- Onomichi in MayJapan · 52 kmHigh 22.4°C · Low 13.8°C · 124 mm rain
- Mihara in MayJapan · 53 kmHigh 22.9°C · Low 13.9°C · 129 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Niihama) is explained once on the Niihama year overview and on the Sources, method and limits page.
Saijō lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.