Aso weather in December

In December, Aso sees average daytime highs of 10°C and overnight lows near 1°C, with 69 mm of precipitation across 8.6 wet days and about 9.9 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 30% of the time in December, and the air most often feels dry.

Daylight stretches from about 10 hours at the start of December to 9 h 54 min by month's end. Set against the rest of the year, December is Aso's 3rd-clearest and 6th-windiest month. For the whole year in context, see Aso's year-round climate.

Daytime high
10°
10th warmest
Overnight low
3rd coldest
Precipitation
69 mm
8.6 wet days
Daylight
9 h 48 min
7:17 AM – 5:07 PM
Cloud cover
54%
3rd clearest
Wind
7 km/h
6th windiest
Solar energy
2.33 kWh/m²
Travel score
2.4
out of 10

Aso is city in Kumamoto Prefecture, Japan.

Density
72/km²
people per km²
Founded
2005

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 Aso reaches about 10°C in the afternoon and slips back to 1°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 5°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)
1133
2123
3122
4122
5122
6112
7112
8112
9112
10111
11101
12101
13101
14101
15101
16101
17101
18101
1991
2091
2190
2290
2390
2490
2590
2690
2790
2890
2990
3090
3190

How December really feels in Aso

Once humidity and wind are folded in, December averages 0 days that feel above 32°C and 26 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
26
wind chill below the day's low

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

Aso 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 / -1°698.82.810.11.2
Feb / 929.42.110.81.9
Mar13° / 14012.80.911.73.6
Apr18° / 15811.70.112.85.5
May23° / 13°18112.4013.76.3
Jun25° / 18°41318014.15.2
Jul28° / 21°31918.80144.4
Aug30° / 22°16416.3013.24.4
Sep27° / 18°16512.9012.26.0
Oct22° / 12°1027.7011.27.1
Nov16° / 818.1010.35.3
Dec10° / 698.61.39.92.4

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 30% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 23% of December, with mostly cloudy or overcast conditions the remaining 47%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15644
25743
35644
45644
55545
65545
75545
85545
95446
105446
115446
125446
135446
145446
155446
165347
175347
185347
195248
205347
215248
225248
235248
245248
255248
265248
275248
285149
295149
305149
315050

Chance of precipitation in December

Any precipitationSnow

Aso gets around 69 mm of rain and snow over 8.6 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 27% and peaks near 30% on the wettest days, and about 1 day brings snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1292
2292
3302
4302
5302
6302
7292
8293
9293
10283
11283
12283
13273
14274
15274
16274
17274
18274
19275
20265
21265
22265
23266
24266
25267
26267
27267
28268
29268
30268
31268

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 (%)
1973
2982
3982
4982
5982
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 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 10 hours at the start of December to 9 h 54 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 7:06 AM to 7:23 AM, and sunset from 5:05 PM to 5:14 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
110.07:065:05
210.07:075:05
310.07:085:05
49.97:085:05
59.97:095:05
69.97:105:05
79.97:115:05
89.97:115:05
99.97:125:05
109.97:135:05
119.97:135:06
129.97:145:06
139.97:155:06
149.87:155:06
159.87:165:07
169.87:175:07
179.87:175:07
189.87:185:08
199.87:185:08
209.87:195:09
219.87:195:09
229.87:205:09
239.87:205:10
249.87:215:10
259.87:215:11
269.87:225:11
279.87:225:12
289.87:225:13
299.87:235:13
309.87:235:14
319.97:235:14

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.33 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.33 kWh/m² to a high of 5.19 kWh/m² in May across the year — December's 2.33 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.4Moderate
22.4Moderate
32.4Moderate
42.4Moderate
52.4Moderate
62.4Moderate
72.4Moderate
82.3Moderate
92.3Moderate
102.3Moderate
112.3Moderate
122.3Moderate
132.3Moderate
142.3Moderate
152.3Moderate
162.3Moderate
172.3Moderate
182.3Moderate
192.3Moderate
202.3Moderate
212.3Moderate
222.3Moderate
232.4Moderate
242.4Moderate
252.4Moderate
262.4Moderate
272.4Moderate
282.4Moderate
292.4Moderate
302.4Moderate
312.4Moderate
Planning a trip in December

Hazard calendar for Aso

In seasonPeak

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

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

Aso's rainy season runs June–July, 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 Aso?

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

2.4
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 Aso.

What to pack for Aso in December

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

In December, Aso sees daytime highs around 10°C and nights near 1°C. Pack a warm layer. Worth having: rain gear. About 9 days see rain.

a warm layerrain gear

Sea temperature near Aso in December

The nearest coast averages about 17°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 43 km away) is warmest in August at about 27°C and coldest in February near 13°C.

It's comfortable for a long swim from May 27 to Nov 13 — about 5.6 months when the water holds above 20°C.

10°15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan14Bracing
Feb13Bracing
Mar14Bracing
Apr16Cool
May19Cool
Jun22Refreshing
Jul25Warm
Aug27Warm
Sep26Warm
Oct23Refreshing
Nov20Cool
Dec17Cool

UV index in Aso in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 3 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Aso peaks around June 23 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highModerateJun 23UV 10Dec 22UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar7High
Apr8Very high
May9Very high
Jun11Extreme
Jul10Extreme
Aug10Very high
Sep10Very high
Oct7High
Nov4Moderate
Dec3Moderate

Air quality in Aso 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 Aso is worst in March — around 30 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (September, 14 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateMar 1829 µg/m³Sep 2214 µg/m³
PM2.5 (µg/m³)Level
Jan17Moderate
Feb20Moderate
Mar30Moderate
Apr24Moderate
May22Moderate
Jun19Moderate
Jul14Moderate
Aug15Moderate
Sep14Moderate
Oct14Moderate
Nov15Moderate
Dec14Moderate
Location & terrain

Where is Aso?

Aso sits at 32.9°N, 131.1°E, 520 m above sea level, in Japan. The nearest listed city is Ōzu, 20 km away.

Topography around Aso

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

Within 3 km, the terrain around Aso has significant variations in elevation — a maximum elevation change of 428 m around an average of 568 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,443 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,757 m.

The land around Aso is covered by cropland (53%) and trees (29%) within 3 km, trees (65%) and cropland (20%) within 16 km, and trees (71%) within 80 km.

3 km
428 m
16 km
1,443 m
80 km
1,757 m
treesgrasslandcroplandartificial surfaceswater
December weather nearby: Ōzu 20 km · Kikuchi 25 km · Okino 28 km · Kōshi 29 km · Takedamachi 30 km · Shimada 34 km · Mifune 34 km · Kotō 36 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 Aso (32.9373°, 131.0801°, elevation 520 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).