Shiojiri weather in December

In December, Shiojiri sees average daytime highs of 5°C and overnight lows near -4°C, with 84 mm of precipitation across 12 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 7°C in the first days to 3°C by the end. The sky is clear or mostly clear about 37% 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 Shiojiri's 1st-clearest and 5th-windiest month. For the whole year in context, see Shiojiri's year-round climate.

Daytime high
10th warmest
Overnight low
-4°
3rd coldest
Precipitation
84 mm
12 wet days
Daylight
9 h 36 min
6:58 AM – 4:31 PM
Cloud cover
52%
1st clearest
Wind
7 km/h
5th windiest
Solar energy
2.54 kWh/m²
Travel score
0.2
out of 10

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 7°C in the first days to 3°C by the end.

A typical December day in Shiojiri reaches about 5°C in the afternoon and slips back to -4°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 0°C and 9°C. Set against its neighbours, December runs about 6°C cooler than November and about 3°C warmer than January.

-10°10°151015202531
Avg high (°C)Avg low (°C)
18-1
28-1
37-2
47-2
57-2
67-2
76-3
86-3
96-3
106-3
115-3
125-4
135-4
145-4
155-4
165-4
174-5
184-5
194-5
204-5
214-5
224-5
234-5
243-6
253-6
263-6
273-6
283-6
293-6
303-6
313-6

How December really feels in Shiojiri

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.

Shiojiri 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 / -8°8511.512.49.80.0
Feb / -7°8610.19.510.60.0
Mar / -3°14213.38.911.70.9
Apr14° / 12712.41.912.93.7
May19° / 13312.10.113.95.7
Jun22° / 14°17815.5014.45.4
Jul26° / 18°19817014.25.5
Aug27° / 18°12313.4013.45.9
Sep23° / 15°15912.8012.26.1
Oct17° / 17012.10.111.15.2
Nov11° / 9710.41.710.12.8
Dec / -4°84129.49.60.2

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% of the time in December, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 19% of December, with mostly cloudy or overcast conditions the remaining 44%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15644
25644
35644
45644
55644
65644
75644
85644
95545
105644
115545
125545
135644
145545
155545
165545
175644
185644
195644
205743
215743
225743
235743
245842
255842
265842
275842
285842
295842
305842
315842

Chance of precipitation in December

Any precipitationSnow

Shiojiri gets around 84 mm of rain and snow over 12 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 38% and peaks near 40% on the wettest days, and about 9 days bring snow.

0%10%20%30%40%50%151015202531
Rain chance (%)Snow chance (%)
13615
23716
33717
43718
53719
63821
73822
83924
93925
103926
113927
124028
134029
144030
153931
163932
173932
183933
193933
203934
213834
223835
233835
243836
253836
263736
273737
283737
293738
303738
313738

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 7 km/h in December.

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

0246810151015202531
Wind speed (km/h)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

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 6:46 AM to 7:04 AM, and sunset from 4:30 PM to 4:39 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.76:464:30
29.76:474:29
39.76:484:29
49.76:494:29
59.76:504:29
69.66:504:29
79.66:514:29
89.66:524:29
99.66:534:30
109.66:534:30
119.66:544:30
129.66:554:30
139.66:564:30
149.66:564:30
159.66:574:31
169.66:584:31
179.66:584:31
189.56:594:32
199.56:594:32
209.57:004:32
219.57:004:33
229.57:014:33
239.57:014:34
249.57:024:34
259.57:024:35
269.57:034:35
279.67:034:36
289.67:034:37
299.67:034:37
309.67:044:38
319.67:044:39

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.54 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.54 kWh/m² to a high of 5.73 kWh/m² in May across the year — December's 2.54 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
152.5Moderate
162.5Moderate
172.5Moderate
182.6Moderate
192.6Moderate
202.6Moderate
212.6Moderate
222.6Moderate
232.6Moderate
242.6Moderate
252.7Moderate
262.7Moderate
272.7Moderate
282.7Moderate
292.7Moderate
302.7Moderate
312.8Moderate
Planning a trip in December

Is December a good time to visit Shiojiri?

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

0.2
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 Shiojiri.

What to pack for Shiojiri in December

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

In December, Shiojiri sees daytime highs around 5°C and nights near -4°C. Pack a warm layer and a heavy coat. Worth having: rain gear. About 12 days see rain.

a warm layera heavy coatrain gear

UV index in Shiojiri 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 Shiojiri peaks around July 14 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 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 14UV 11Dec 21UV 2
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7Very high
May9Very high
Jun10Extreme
Jul11Extreme
Aug10Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec2Moderate

Air quality in Shiojiri 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 Shiojiri is worst in April — around 18 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (December, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1918 µg/m³Dec 178 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb11Good
Mar17Moderate
Apr18Moderate
May17Moderate
Jun16Moderate
Jul13Moderate
Aug12Good
Sep10Good
Oct10Good
Nov9Good
Dec8Good
Location & terrain

Where is Shiojiri?

Shiojiri sits at 36.1°N, 138.0°E, 729 m above sea level, in Japan. The nearest listed city is Okaya, 9.0 km away.

Topography around Shiojiri

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

Within 3 km, the terrain around Shiojiri has significant variations in elevation — a maximum elevation change of 527 m around an average of 821 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,395 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,051 m.

The land around Shiojiri is covered by trees (52%) and artificial surfaces (23%) within 3 km, trees (68%) within 16 km, and trees (87%) within 80 km.

3 km
527 m
16 km
1,395 m
80 km
3,051 m
treesgrasslandcroplandartificial surfaceswater
December weather nearby: Okaya 9.0 km · Shimosuwa 11 km · Tatsuno 13 km · Matsumoto 15 km · Suwa 15 km · Chino 21 km · Azumino 22 km · Kinoshita 22 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 Shiojiri (36.1°, 137.9667°, elevation 729 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).