Climate averages 1991–2020
Iwamizawa weather
in December.
A freezing month with moderate precipitation: the 10th warmest and the 6th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a freezing month in Iwamizawa: daytime highs average -0.8°C and nights cool to about -8.0°C. By daytime temperature it is the 10th warmest of the 12 months.
Expect about 69 mm of precipitation on roughly 15 days, which makes December a month with moderate precipitation (the 6th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 9 h 03 min on an average December day.
The nearest other city in this atlas is Ebetsu (20 km away). In December its highs average -0.9°C, about as warm as Iwamizawa, with 62 mm of precipitation.
Among the 303 cities listed in Japan, Iwamizawa ranks joint 299th of 303 for the warmest December highs and joint 164th of 303 for the driest December (precipitation, lowest first). The mean December high of those 303 cities is 9.5°C; Iwamizawa is 10.3°C cooler than that mean.
From December to January, average highs fall by 2.7°C to -3.5°C, and monthly precipitation falls from 69 mm to 49 mm.
The annual picture
December 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 | 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, selected | -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
December in nearby cities
- Ebetsu in DecemberJapan · 20 kmHigh -0.9°C · Low -7.1°C · 62 mm precipitation
- Sapporo in DecemberJapan · 36 kmHigh -0.3°C · Low -5.3°C · 73 mm precipitation
- Eniwa in DecemberJapan · 37 kmHigh -0.3°C · Low -6.5°C · 62 mm precipitation
- Chitose in DecemberJapan · 43 kmHigh 0.5°C · Low -5.6°C · 54 mm precipitation
- Otaru in DecemberJapan · 61 kmHigh 0.3°C · Low -2.7°C · 125 mm precipitation
- Tomakomai in DecemberJapan · 64 kmHigh 0.7°C · Low -4.2°C · 63 mm precipitation
- Asahikawa in DecemberJapan · 80 kmHigh -3.0°C · Low -10.1°C · 83 mm precipitation
- Muroran in DecemberJapan · 117 kmHigh 0.3°C · Low -4.2°C · 69 mm precipitation
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.