Yamaguchi weather in December

In December, Yamaguchi sees average daytime highs of 11°C and overnight lows near 4°C, with 64 mm of precipitation across 9.7 wet days and about 9.8 hours of daylight. It is the 10th-warmest and 11th-wettest month of the year here.

Highs ease over the month, from about 13°C in the first days to 10°C by the end. The sky is clear or mostly clear about 21% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 54 min at the start of December to 9 h 42 min by month's end. Set against the rest of the year, December is Yamaguchi's 4th-clearest and 3rd-windiest month. For the whole year in context, see Yamaguchi's year-round climate.

Daytime high
11°
10th warmest
Overnight low
3rd coldest
Precipitation
64 mm
9.7 wet days
Daylight
9 h 42 min
7:18 AM – 5:02 PM
Cloud cover
60%
4th clearest
Wind
10 km/h
3rd windiest
Solar energy
2.17 kWh/m²
Travel score
2.9
out of 10

Yamaguchi is capital city of Yamaguchi prefecture.

Density
190/km²
people per km²
Founded
1929

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 13°C in the first days to 10°C by the end.

A typical December day in Yamaguchi reaches about 11°C in the afternoon and slips back to 4°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 7°C and 15°C. Set against its neighbours, December runs about 6°C cooler than November and about 2°C warmer than January.

-5°10°15°20°151015202531
Avg high (°C)Avg low (°C)
1146
2136
3135
4135
5135
6135
7125
8125
9125
10124
11124
12124
13114
14114
15114
16114
17114
18114
19114
20114
21113
22103
23103
24103
25103
26103
27103
28103
29103
30103
31103

How December really feels in Yamaguchi

Once humidity and wind are folded in, December averages 0 days that feel above 32°C and 3 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
3
wind chill below the day's low

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

Yamaguchi weather by month

How December compares with the rest of the year at a glance. December is the 10th-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 629.72.2101.7
Feb10° / 709.81.810.72.2
Mar14° / 11711.40.411.73.8
Apr19° / 13010.6012.85.9
May23° / 14°15010.5013.86.7
Jun26° / 19°24914.3014.25.7
Jul30° / 23°28316.30144.2
Aug31° / 24°16714.2013.33.9
Sep28° / 20°17812.4012.25.7
Oct23° / 14°978.1011.17.1
Nov17° / 788.2010.25.6
Dec11° / 649.70.99.82.9

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 21% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 25% of December, with mostly cloudy or overcast conditions the remaining 54%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15347
25347
35149
45149
55050
64951
75050
84852
94753
104753
114555
124654
134555
144555
154456
164357
174357
184357
194357
204456
214456
224456
234456
244456
254555
264654
274555
284555
294555
304456
314357

Chance of precipitation in December

Any precipitationSnow

Yamaguchi gets around 64 mm of rain and snow over 9.7 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 31% and peaks near 31% on the wettest days, and about 1 day brings snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1300
2300
3300
4311
5311
6311
7311
8311
9311
10311
11311
12312
13312
14312
15312
16313
17313
18313
19313
20314
21314
22314
23315
24315
25315
26315
27316
28316
29306
30306
31306

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 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1982
2982
3982
4982
5991
6991
7991
8991
9991
10991
11991
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 10 km/h in December.

Across December, daily wind ranges from about 10 km/h on the calmest days to 11 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
110calm
210calm
310calm
410calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1810calm
1910calm
2010calm
2110calm
2210calm
2310calm
2410calm
2510calm
2611calm
2711calm
2811calm
2911calm
3011calm
3111calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 54 min at the start of December to 9 h 42 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 7:07 AM to 7:25 AM, and sunset from 5:00 PM to 5:10 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.97:075:00
29.97:085:00
39.97:095:00
49.87:105:00
59.87:115:00
69.87:115:00
79.87:125:00
89.87:135:00
99.87:145:01
109.87:145:01
119.87:155:01
129.87:165:01
139.77:165:01
149.77:175:02
159.77:185:02
169.77:185:02
179.77:195:03
189.77:205:03
199.77:205:03
209.77:215:04
219.77:215:04
229.77:225:05
239.77:225:05
249.77:235:06
259.77:235:06
269.77:235:07
279.77:245:07
289.77:245:08
299.77:245:08
309.77:255:09
319.77:255:10

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.17 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.17 kWh/m² to a high of 5.6 kWh/m² in May across the year — December's 2.17 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.3Moderate
22.3Moderate
32.3Moderate
42.3Moderate
52.3Moderate
62.2Moderate
72.2Moderate
82.2Moderate
92.2Moderate
102.2Moderate
112.2Moderate
122.2Moderate
132.1Moderate
142.1Moderate
152.1Moderate
162.1Moderate
172.1Moderate
182.1Moderate
192.1Moderate
202.1Moderate
212.2Moderate
222.2Moderate
232.2Moderate
242.2Moderate
252.2Moderate
262.2Moderate
272.2Moderate
282.2Moderate
292.2Moderate
302.3Moderate
312.3Moderate
Planning a trip in December

Hazard calendar for Yamaguchi

In seasonPeak

In December, Yamaguchi sits inside its pacific typhoon season. The full year is below, with each hazard's peak months called out.

Yamaguchi sits in the Pacific typhoon belt; the season peaks July–October.

Yamaguchi's rainy season runs April–September, when most of the year's rain falls.

Pacific typhoon
Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is December a good time to visit Yamaguchi?

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 Yamaguchi.

What to pack for Yamaguchi in December

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

In December, Yamaguchi sees daytime highs around 11°C and nights near 4°C. Pack a warm layer. Worth having: rain gear. About 10 days see rain.

a warm layerrain gear

Sea temperature near Yamaguchi in December

The nearest coast averages about 16°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 35 km away) is warmest in August at about 27°C and coldest in February near 12°C.

It's comfortable for a long swim from Jun 7 to Nov 11 — about 5.2 months when the water holds above 20°C.

10°15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan13Bracing
Feb12Bracing
Mar12Bracing
Apr14Bracing
May17Cool
Jun21Refreshing
Jul25Warm
Aug27Warm
Sep26Warm
Oct23Refreshing
Nov20Cool
Dec16Cool

UV index in Yamaguchi in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 3. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Yamaguchi peaks around June 21 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 3 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateJun 21UV 10Dec 21UV 3
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar6High
Apr7Very high
May8Very high
Jun10Very high
Jul10Very high
Aug9Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Yamaguchi 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 Yamaguchi is worst in April — around 23 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 11 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateApr 1023 µg/m³Oct 1111 µg/m³
PM2.5 (µg/m³)Level
Jan16Moderate
Feb19Moderate
Mar23Moderate
Apr23Moderate
May20Moderate
Jun16Moderate
Jul13Moderate
Aug15Moderate
Sep11Good
Oct11Good
Nov13Moderate
Dec12Moderate
Location & terrain

Where is Yamaguchi?

Yamaguchi sits at 34.2°N, 131.5°E, 157 m above sea level, in Japan. The nearest listed city is Ogōri-shimogō, 11 km away.

Topography around Yamaguchi

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

Within 3 km, the terrain around Yamaguchi has significant variations in elevation — a maximum elevation change of 424 m around an average of 118 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 780 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,369 m.

The land around Yamaguchi is covered by trees (60%) and artificial surfaces (35%) within 3 km, trees (83%) within 16 km, and water (51%) and trees (42%) within 80 km.

3 km
424 m
16 km
780 m
80 km
1,369 m
treesgrasslandcroplandartificial surfaceswater
December weather nearby: Ogōri-shimogō 11 km · Hōfu 17 km · Mine 23 km · Hagi 25 km · Sanyōonoda 33 km · Onoda 33 km · Nagato 33 km · Ube 33 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 Yamaguchi (34.1833°, 131.4667°, elevation 157 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).