Climate averages 1991–2020
Oyama weather
in December.
A cool, moderately wet month: the 10th warmest and the driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a cool month in Oyama: daytime highs average 9.7°C and nights cool to about 0.4°C. By daytime temperature it is the 10th warmest of the 12 months.
Expect about 54 mm of rain on roughly 7 days, which makes December a moderately wet month (the driest month of the year). Daylight, from sunrise to sunset, lasts about 9 h 44 min on an average December day.
The nearest other city in this atlas is Tochigi (11 km away). In December its highs average 9.5°C, about as warm as Oyama, with 55 mm of rain.
Among the 303 cities listed in Japan, Oyama ranks joint 205th of 303 for the warmest December highs and joint 33rd of 303 for the driest December (rainfall, lowest first). The mean December high of those 303 cities is 9.5°C; Oyama is 0.2°C warmer than that mean.
From December to January, average highs fall by 2.4°C to 7.3°C, and monthly rainfall rises from 54 mm to 55 mm.
The annual picture
December 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
Oyama climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.3°C-2.1°C | -2.1°C | 55 | 6.0 | 10.010 h |
| February | 8.4°C-1.5°C | -1.5°C | 55 | 6.9 | 10.811 h |
| March | 12.2°C1.6°C | 1.6°C | 106 | 11.6 | 11.912 h |
| April | 17.4°C6.8°C | 6.8°C | 120 | 12.6 | 13.113 h |
| May | 22.1°C12.4°C | 12.4°C | 153 | 13.7 | 14.114 h |
| June | 24.7°C16.9°C | 16.9°C | 177 | 16.5 | 14.615 h |
| July | 28.2°C21.0°C | 21.0°C | 209 | 18.7 | 14.414 h |
| August | 29.5°C22.3°C | 22.3°C | 161 | 16.3 | 13.514 h |
| September | 25.7°C18.9°C | 18.9°C | 206 | 16.2 | 12.412 h |
| October | 20.2°C12.7°C | 12.7°C | 200 | 13.9 | 11.311 h |
| November | 14.9°C5.9°C | 5.9°C | 88 | 9.4 | 10.310 h |
| December, selected | 9.7°C0.4°C | 0.4°C | 54 | 6.8 | 9.710 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
December in nearby cities
- Tochigi in DecemberJapan · 11 kmHigh 9.5°C · Low 0.4°C · 55 mm rain
- Koga in DecemberJapan · 15 kmHigh 10.0°C · Low 0.7°C · 54 mm rain
- Chikusei in DecemberJapan · 16 kmHigh 10.1°C · Low 0.7°C · 52 mm rain
- Sano in DecemberJapan · 20 kmHigh 9.8°C · Low 0.5°C · 51 mm rain
- Mooka in DecemberJapan · 24 kmHigh 9.8°C · Low 0.0°C · 49 mm rain
- Tatebayashi in DecemberJapan · 25 kmHigh 9.8°C · Low 0.7°C · 51 mm rain
- Kazo in DecemberJapan · 27 kmHigh 10.3°C · Low 0.8°C · 49 mm rain
- Kukichūō in DecemberJapan · 28 kmHigh 10.3°C · Low 0.8°C · 52 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 Oyama) is explained once on the Oyama year overview and on the Sources, method and limits page.
Koga lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.