Climate averages 1991–2020
Iwamizawa weather
in May.
A mild, moderately wet month: the 5th warmest and the 7th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a mild month in Iwamizawa: daytime highs average 16.2°C and nights cool to about 6.8°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 83 mm of rain on roughly 11 days, which makes May a moderately wet month (the 7th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 39 min on an average May day.
The nearest other city in this atlas is Ebetsu (20 km away). In May its highs average 15.8°C, about as warm as Iwamizawa, with 84 mm of rain.
Among the 303 cities listed in Japan, Iwamizawa ranks 292nd of 303 for the warmest May highs and 2nd of 303 for the driest May (rainfall, lowest first). The mean May high of those 303 cities is 21.3°C; Iwamizawa is 5.2°C cooler than that mean.
From May to June, average highs rise by 3.9°C to 20.1°C, and monthly rainfall falls from 83 mm to 64 mm.
The annual picture
May in context
Monthly precipitation
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
Iwamizawa climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -3.5°C-10.8°C | -10.8°C | 49 | 12.9 | 9.49 h |
| February | -2.5°C-10.0°C | -10.0°C | 43 | 10.8 | 10.510 h |
| March | 1.9°C-5.9°C | -5.9°C | 57 | 11.6 | 11.912 h |
| April | 9.5°C0.1°C | 0.1°C | 67 | 11.8 | 13.413 h |
| May, selected | 16.2°C6.8°C | 6.8°C | 83 | 11.4 | 14.615 h |
| June | 20.1°C11.8°C | 11.8°C | 64 | 9.6 | 15.315 h |
| July | 23.7°C16.3°C | 16.3°C | 113 | 11.5 | 15.015 h |
| August | 24.4°C17.5°C | 17.5°C | 161 | 12.5 | 14.014 h |
| September | 20.8°C13.1°C | 13.1°C | 126 | 13.2 | 12.513 h |
| October | 14.4°C6.3°C | 6.3°C | 92 | 13.6 | 11.111 h |
| November | 6.7°C-0.5°C | -0.5°C | 87 | 16.1 | 9.810 h |
| December | -0.8°C-8.0°C | -8.0°C | 69 | 15.3 | 9.19 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet 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
- Ebetsu in MayJapan · 20 kmHigh 15.8°C · Low 6.5°C · 84 mm rain
- Sapporo in MayJapan · 36 kmHigh 16.1°C · Low 6.7°C · 93 mm rain
- Eniwa in MayJapan · 37 kmHigh 15.0°C · Low 6.2°C · 84 mm rain
- Chitose in MayJapan · 43 kmHigh 14.1°C · Low 6.5°C · 95 mm rain
- Otaru in MayJapan · 61 kmHigh 15.1°C · Low 7.0°C · 84 mm rain
- Tomakomai in MayJapan · 64 kmHigh 12.7°C · Low 6.7°C · 109 mm rain
- Asahikawa in MayJapan · 80 kmHigh 15.9°C · Low 5.6°C · 91 mm rain
- Muroran in MayJapan · 117 kmHigh 13.2°C · Low 7.0°C · 112 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 Iwamizawa) is explained once on the Iwamizawa year overview and on the Sources, method and limits page.