Oyama weather in December

In December, Oyama sees average daytime highs of 11°C and overnight lows near 2°C, with 54 mm of precipitation across 6.8 wet days and about 9.6 hours of daylight. It is the 10th-warmest and 12th-wettest month of the year here.

Highs ease over the month, from about 12°C in the first days to 9°C by the end. The sky is clear or mostly clear about 60% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 42 min at the start of December to 9 h 36 min by month's end. Set against the rest of the year, December is Oyama's 2nd-clearest and 6th-windiest month. For the whole year in context, see Oyama's year-round climate.

Daytime high
11°
10th warmest
Overnight low
3rd coldest
Precipitation
54 mm
6.8 wet days
Daylight
9 h 30 min
6:51 AM – 4:23 PM
Cloud cover
38%
2nd clearest
Wind
8 km/h
6th windiest
Solar energy
2.38 kWh/m²
Travel score
2.9
out of 10

Oyama is city in Tochigi prefecture, Japan.

Density
976/km²
people per km²
Founded
1954

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 12°C in the first days to 9°C by the end.

A typical December day in Oyama reaches about 11°C in the afternoon and slips back to 2°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 7°C and 14°C. Set against its neighbours, December runs about 5°C cooler than November and about 2°C warmer than January.

-5°10°15°20°151015202531
Avg high (°C)Avg low (°C)
1134
2134
3124
4124
5124
6123
7123
8123
9113
10113
11113
12112
13112
14112
15112
16102
17102
18102
19101
20101
21101
22101
23101
24101
25101
2691
2791
2891
2991
3090
3190

How December really feels in Oyama

Once humidity and wind are folded in, December averages 0 days that feel above 32°C and 19 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
19
wind chill below the day's low

The story in December is cold — wind chill drags the overnight "feels like" below the raw low.

Oyama weather by month

How December compares with the rest of the year at a glance. December is the 10th-warmest and 12th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -0°5561.89.81.7
Feb / 546.92.210.62.1
Mar13° / 10611.61.311.73.5
Apr18° / 12012.60.212.95.4
May23° / 14°15313.7013.96.1
Jun25° / 18°17716.5014.45.3
Jul29° / 22°20918.7014.24.3
Aug30° / 23°16116.3013.44.1
Sep26° / 20°20616.2012.25.3
Oct21° / 14°20013.9011.15.9
Nov16° / 889.4010.15.0
Dec11° / 546.80.49.62.9

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 60% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 13% of December, with mostly cloudy or overcast conditions the remaining 27%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16436
26436
36535
46535
56634
66733
76832
86931
97030
107129
117228
127228
137327
147327
157327
167426
177426
187525
197525
207624
217624
227624
237624
247723
257723
267723
277822
287822
297822
307822
318020

Chance of precipitation in December

Any precipitationSnow

Oyama gets around 54 mm of rain and snow over 6.8 wet days in December, the driest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 22% and peaks near 29% on the wettest days, and about 0 day brings snow. The odds ease toward the end of the month.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1291
2281
3281
4271
5271
6261
7261
8251
9251
10241
11241
12232
13232
14222
15222
16212
17212
18212
19201
20202
21192
22192
23182
24182
25172
26172
27172
28162
29162
30162
31163

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

Most of December feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, December lands in the dry band about 100% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1991
2991
31000
41000
51000
61000
71000
81000
91000
101000
111000
121000
131000
141000
151000
161000
171000
181000
191000
201000
211000
221000
231000
241000
251000
261000
271000
281000
291000
301000
311000

Wind in December

Winds average 8 km/h in December.

Across December, daily wind ranges from about 7 km/h on the calmest days to 8 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
158calm
168calm
178calm
188calm
198calm
208calm
218calm
228calm
238calm
248calm
258calm
268calm
278calm
288calm
298calm
308calm
318calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 42 min at the start of December to 9 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 6 minutes over December. Sunrise moves from 6:39 AM to 6:57 AM, and sunset from 4:22 PM to 4:31 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.76:394:22
29.76:404:22
39.76:414:22
49.76:424:21
59.66:434:21
69.66:444:21
79.66:444:22
89.66:454:22
99.66:464:22
109.66:474:22
119.66:474:22
129.66:484:22
139.66:494:22
149.66:504:23
159.56:504:23
169.56:514:23
179.56:514:23
189.56:524:24
199.56:534:24
209.56:534:25
219.56:544:25
229.56:544:25
239.56:554:26
249.56:554:26
259.56:554:27
269.56:564:28
279.56:564:28
289.56:564:29
299.56:574:29
309.66:574:30
319.66:574:31

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.38 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.38 kWh/m² to a high of 5.07 kWh/m² in May across the year — December's 2.38 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.3Moderate
22.3Moderate
32.3Moderate
42.3Moderate
52.3Moderate
62.3Moderate
72.3Moderate
82.3Moderate
92.3Moderate
102.3Moderate
112.3Moderate
122.4Moderate
132.4Moderate
142.4Moderate
152.4Moderate
162.4Moderate
172.4Moderate
182.4Moderate
192.4Moderate
202.5Moderate
212.5Moderate
222.5Moderate
232.5Moderate
242.5Moderate
252.5Moderate
262.6Moderate
272.6Moderate
282.6Moderate
292.6Moderate
302.6Moderate
312.7Moderate
Planning a trip in December

Is December a good time to visit Oyama?

Our two travel scores rate December for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

2.9
Sightseeing
10th-best month of the year
0.0
Beach & pool
10th-best month of the year

December is a weaker month for outdoor sightseeing in Oyama.

What to pack for Oyama in December

From December's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In December, Oyama sees daytime highs around 11°C and nights near 2°C. Pack a warm layer. About 7 days see rain.

a warm layer

UV index in Oyama in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Oyama peaks around July 17 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 2 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateJul 17UV 9Jan 1UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar4Moderate
Apr6High
May8Very high
Jun9Very high
Jul10Very high
Aug9Very high
Sep8Very high
Oct6High
Nov3Moderate
Dec2Moderate

Air quality in Oyama in December

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where December falls, not just the annual average.

Air quality in Oyama is worst in April — around 26 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (December, 14 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateApr 1426 µg/m³Dec 1814 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb21Moderate
Mar25Moderate
Apr26Moderate
May24Moderate
Jun20Moderate
Jul17Moderate
Aug16Moderate
Sep16Moderate
Oct16Moderate
Nov16Moderate
Dec14Moderate
Location & terrain

Where is Oyama?

Oyama sits at 36.3°N, 139.8°E, 41 m above sea level, in Japan. The nearest listed city is Yūki, 7.0 km away.

Topography around Oyama

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Oyama.

Within 3 km, the terrain around Oyama has only modest variations in elevation — a maximum elevation change of 39 m around an average of 33 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 393 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,553 m.

The land around Oyama is covered by artificial surfaces (62%) within 3 km, cropland (47%) and artificial surfaces (30%) within 16 km, and trees (48%), artificial surfaces (25%) and cropland (21%) within 80 km.

3 km
39 m
16 km
393 m
80 km
2,553 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
December weather nearby: Yūki 7.0 km · Nogi 10 km · Tochigi 11 km · Mibu 13 km · Shimotsuke 14 km · Fujioka 15 km · Koga 15 km · Yachiyo 15 km

Japan travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type A / B
100 V · 50 / 60 Hz
Prices
≈ 65% of US
price level, 2025
GDP per capita
$35,951
2025
Happiness
6.1 / 10
World Happiness, 2025
Safe drinking water
99%
of population, 2024
Homicide rate
0.2
per 100k, 2023
Road deaths
3.6
per 100k/yr, 2019
Income group
High
World Bank
English
Very low
EF EPI 446
Religion
Shintoism 49%Buddhism 46%other 4%Christianity 1%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Oyama (36.3°, 139.8°, elevation 41 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).