Kōshū weather in December

In December, Kōshū sees average daytime highs of 6°C and overnight lows near -3°C, with 60 mm of precipitation across 7.6 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 8°C in the first days to 4°C by the end. The sky is clear or mostly clear about 56% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 48 min at the start of December to 9 h 36 min by month's end. Set against the rest of the year, December is Kōshū's 2nd-clearest and 5th-windiest month. For the whole year in context, see Kōshū's year-round climate.

Daytime high
10th warmest
Overnight low
-3°
3rd coldest
Precipitation
60 mm
7.6 wet days
Daylight
9 h 36 min
6:53 AM – 4:29 PM
Cloud cover
41%
2nd clearest
Wind
6 km/h
5th windiest
Solar energy
2.57 kWh/m²
Travel score
0.4
out of 10

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 8°C in the first days to 4°C by the end.

A typical December day in Kōshū reaches about 6°C in the afternoon and slips back to -3°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 2°C and 10°C. Set against its neighbours, December runs about 5°C cooler than November and about 3°C warmer than January.

-10°-5°10°15°151015202531
Avg high (°C)Avg low (°C)
180
280
380
480
57-1
67-1
77-1
87-1
97-1
106-2
116-2
126-2
136-2
146-2
156-2
166-3
175-3
185-3
195-3
205-3
215-3
225-3
235-4
245-4
254-4
264-4
274-4
284-4
294-4
304-4
314-4

How December really feels in Kōshū

Once humidity and wind are folded in, December averages 0 days that feel above 32°C and 31 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
31
wind chill below the day's low

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

Kōshū 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 / -6°6676.59.90.0
Feb / -6°718.46.610.60.0
Mar / -2°12913.57.911.71.0
Apr13° / 13113.92.212.93.5
May18° / 14715.10.213.95.1
Jun21° / 14°20519.8014.44.6
Jul25° / 18°23421.9014.24.8
Aug26° / 18°18921.7013.44.9
Sep22° / 15°22018.6012.25.1
Oct16° / 21215.5011.14.5
Nov11° / 8810.10.510.12.8
Dec / -3°607.64.19.60.4

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 56% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 15% of December, with mostly cloudy or overcast conditions the remaining 28%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16436
26535
36535
46634
56634
66733
76733
86832
96931
106931
117030
127129
137129
147129
157228
167228
177228
187327
197327
207327
217426
227525
237525
247525
257525
267624
277723
287723
297723
307723
317822

Chance of precipitation in December

Any precipitationSnow

Kōshū gets around 60 mm of rain and snow over 7.6 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 24% and peaks near 32% on the wettest days, and about 4 days bring snow. The odds ease toward the end of the month.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1327
2318
3318
4309
5309
62910
72810
82811
92711
102612
112612
122512
132512
142413
152413
162413
172313
182313
192213
202214
212214
222214
232114
242114
252114
262014
272014
282014
291914
301914
311915

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 (%)
1100
2100
3100
4100
5100
6100
7100
8100
9100
10100
11100
12100
13100
14100
15100
16100
17100
18100
19100
20100
21100
22100
23100
24100
25100
26100
27100
28100
29100
30100
31100

Wind in December

Winds average 6 km/h in December.

Across December, daily wind ranges from about 5 km/h on the calmest days to 6 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 48 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 12 minutes over December. Sunrise moves from 6:42 AM to 7:00 AM, and sunset from 4:27 PM to 4:36 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.86:424:27
29.76:434:27
39.76:444:27
49.76:454:27
59.76:454:27
69.76:464:27
79.76:474:27
89.76:484:27
99.66:494:27
109.66:494:27
119.66:504:28
129.66:514:28
139.66:514:28
149.66:524:28
159.66:534:29
169.66:534:29
179.66:544:29
189.66:544:30
199.66:554:30
209.66:564:30
219.66:564:31
229.66:574:31
239.66:574:32
249.66:574:32
259.66:584:33
269.66:584:33
279.66:594:34
289.66:594:34
299.66:594:35
309.66:594:36
319.67:004:36

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.57 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.57 kWh/m² to a high of 5.33 kWh/m² in May across the year — December's 2.57 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.5Moderate
22.5Moderate
32.5Moderate
42.5Moderate
52.5Moderate
62.5Moderate
72.5Moderate
82.5Moderate
92.5Moderate
102.5Moderate
112.5Moderate
122.5Moderate
132.5Moderate
142.5Moderate
152.6Moderate
162.6Moderate
172.6Moderate
182.6Moderate
192.6Moderate
202.6Moderate
212.6Moderate
222.7Moderate
232.7Moderate
242.7Moderate
252.7Moderate
262.8Moderate
272.8Moderate
282.8Moderate
292.8Moderate
302.8Moderate
312.9Moderate
Planning a trip in December

Is December a good time to visit Kōshū?

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

0.4
Sightseeing
10th-best month of the year
0.0
Beach & pool
9th-best month of the year

December is a weaker month for outdoor sightseeing in Kōshū.

What to pack for Kōshū in December

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

In December, Kōshū sees daytime highs around 6°C and nights near -3°C. Pack a warm layer. Worth having: a heavy coat. About 8 days see rain.

a warm layera heavy coat

Sea temperature near Kōshū in December

The nearest coast averages about 18°C in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 68 km away) is warmest in August at about 27°C and coldest in February near 15°C.

It's comfortable for a long swim from May 30 to Nov 23 — about 5.9 months when the water holds above 20°C.

15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb15Cool
Mar15Cool
Apr17Cool
May19Cool
Jun22Refreshing
Jul24Warm
Aug27Warm
Sep26Warm
Oct23Refreshing
Nov21Refreshing
Dec18Cool

UV index in Kōshū 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 Kōshū peaks around July 16 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 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 highExtremeVery highModerateJul 16UV 10Dec 23UV 2
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar6High
Apr7Very high
May9Very high
Jun10Very high
Jul11Extreme
Aug10Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec2Moderate

Air quality in Kōshū 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 Kōshū is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (December, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1821 µg/m³Dec 1810 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar19Moderate
Apr21Moderate
May20Moderate
Jun18Moderate
Jul15Moderate
Aug14Moderate
Sep13Moderate
Oct12Moderate
Nov11Good
Dec10Good
Location & terrain

Where is Kōshū?

Kōshū sits at 35.7°N, 138.8°E, 635 m above sea level, in Japan. The nearest listed city is Enzan, 4.0 km away.

Topography around Kōshū

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

Within 3 km, the terrain around Kōshū has large variations in elevation — a maximum elevation change of 817 m around an average of 795 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,980 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,735 m.

The land around Kōshū is covered by trees (79%) within 3 km, trees (86%) within 16 km, and trees (70%) within 80 km.

3 km
817 m
16 km
1,980 m
80 km
3,735 m
treesgrasslandcroplandartificial surfaceswater
December weather nearby: Enzan 4.0 km · Yamanashi 9.0 km · Isawa 15 km · Fuefuki 16 km · Kofu 20 km · Ōtsuki 22 km · Tsuru 23 km · Shōwa 24 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 Kōshū (35.7242°, 138.7711°, elevation 635 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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).