Karatsu weather in December

In December, Karatsu sees average daytime highs of 12°C and overnight lows near 8°C, with 81 mm of precipitation across 11.1 wet days and about 9.8 hours of daylight. It is the 10th-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 14°C in the first days to 11°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 48 min by month's end. Set against the rest of the year, December is Karatsu's 8th-clearest and 2nd-windiest month. For the whole year in context, see Karatsu's year-round climate.

Daytime high
12°
10th warmest
Overnight low
3rd coldest
Precipitation
81 mm
11.1 wet days
Daylight
9 h 48 min
7:22 AM – 5:10 PM
Cloud cover
64%
8th clearest
Wind
16 km/h
2nd windiest
Solar energy
2.14 kWh/m²
Travel score
3.0
out of 10

Karatsu is city in Saga Prefecture, Japan.

Density
241/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 14°C in the first days to 11°C by the end.

A typical December day in Karatsu reaches about 12°C in the afternoon and slips back to 8°C overnight — a 4°C spread between the day's warmth and the night's chill. On most days the high lands between 8°C and 16°C. Set against its neighbours, December runs about 5°C cooler than November and about 3°C warmer than January.

10°15°20°151015202531
Avg high (°C)Avg low (°C)
11410
21410
31410
41310
5139
6139
7139
8139
9139
10129
11128
12128
13128
14128
15128
16128
17128
18128
19118
20118
21117
22117
23117
24117
25117
26117
27117
28117
29117
30117
31107

How December really feels in Karatsu

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

December sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Karatsu weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 7711.81.2101.9
Feb10° / 7810.30.810.82.2
Mar13° / 12411.60.211.73.5
Apr17° / 12°13411012.85.3
May21° / 16°14310.3013.76.4
Jun24° / 20°27714.7014.25.8
Jul28° / 24°26015.40145.1
Aug29° / 26°16213.7013.24.9
Sep26° / 22°17912.6012.26.2
Oct22° / 18°1038.1011.27.1
Nov17° / 13°959.3010.35.5
Dec12° / 8111.10.39.83.0

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 20% of December, with mostly cloudy or overcast conditions the remaining 60%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14951
24753
34753
44654
54753
64654
74456
84456
94357
104258
114159
124159
133862
143862
153862
163763
173664
183664
193664
203565
213664
223664
233763
243763
253763
263862
273862
283961
293961
303961
313961

Chance of precipitation in December

Any precipitationSnow

Karatsu gets around 81 mm of rain and snow over 11.1 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 35% and peaks near 37% on the wettest days, and about 0 day brings snow.

0%10%20%30%40%50%151015202531
Rain chance (%)Snow chance (%)
1340
2340
3350
4350
5350
6350
7350
8350
9350
10360
11360
12360
13361
14371
15371
16371
17371
18371
19361
20361
21361
22361
23361
24352
25352
26352
27342
28342
29332
30332
31332

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 (%)Humid (%)
19451
29640
39640
49730
59730
69820
79820
89820
99910
109910
119910
129910
139910
149910
159910
169910
1710000
1810000
1910000
2010000
2110000
2210000
2310000
2410000
2510000
2610000
2710000
2810000
2910000
3010000
3110000

Wind in December

Winds average 16 km/h in December.

Across December, daily wind ranges from about 15 km/h on the calmest days to 16 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
115light breeze
215light breeze
315light breeze
415light breeze
515light breeze
615light breeze
715light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1216light breeze
1316light breeze
1416light breeze
1516light breeze
1616light breeze
1716light breeze
1816light breeze
1916light breeze
2016light breeze
2116light breeze
2216light breeze
2316light breeze
2416light breeze
2516light breeze
2616light breeze
2716light breeze
2816light breeze
2916light breeze
3016light breeze
3116light breeze

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 54 min at the start of December to 9 h 48 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 7:12 AM to 7:29 AM, and sunset from 5:08 PM to 5:18 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.97:125:08
29.97:125:08
39.97:135:08
49.97:145:08
59.97:155:08
69.97:165:08
79.97:165:08
89.97:175:08
99.87:185:08
109.87:195:09
119.87:195:09
129.87:205:09
139.87:215:09
149.87:215:10
159.87:225:10
169.87:225:10
179.87:235:10
189.87:245:11
199.87:245:11
209.87:255:12
219.87:255:12
229.87:265:13
239.87:265:13
249.87:275:14
259.87:275:14
269.87:275:15
279.87:285:15
289.87:285:16
299.87:285:16
309.87:295:17
319.87:295:18

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.14 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.14 kWh/m² to a high of 5.41 kWh/m² in May across the year — December's 2.14 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.3Moderate
22.3Moderate
32.3Moderate
42.2Moderate
52.2Moderate
62.2Moderate
72.2Moderate
82.2Moderate
92.2Moderate
102.1Moderate
112.1Moderate
122.1Moderate
132.1Moderate
142.1Moderate
152.1Moderate
162.1Moderate
172.1Moderate
182.1Moderate
192.1Moderate
202.1Moderate
212.1Moderate
222.1Moderate
232.1Moderate
242.1Moderate
252.2Moderate
262.2Moderate
272.2Moderate
282.2Moderate
292.2Moderate
302.2Moderate
312.2Moderate
Planning a trip in December

Hazard calendar for Karatsu

In seasonPeak

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

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

Karatsu'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 Karatsu?

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

3.0
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 Karatsu.

What to pack for Karatsu in December

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

In December, Karatsu sees daytime highs around 12°C and nights near 8°C. Pack a warm layer. Worth having: rain gear. About 11 days see rain.

a warm layerrain gear

Sea temperature near Karatsu 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 22 km away) is warmest in August at about 27°C and coldest in February near 14°C.

It's comfortable for a long swim from Jun 8 to Nov 21 — about 5.5 months when the water holds above 20°C.

15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb14Bracing
Mar14Bracing
Apr16Cool
May18Cool
Jun21Refreshing
Jul24Warm
Aug27Warm
Sep25Warm
Oct23Refreshing
Nov21Refreshing
Dec18Cool

UV index in Karatsu 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 Karatsu peaks around July 23 at about 9 (very high) — 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 — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateJul 23UV 9Dec 22UV 3
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar6High
Apr8Very high
May8Very high
Jun7Very high
Jul9Very high
Aug9Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Karatsu 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 Karatsu is worst in April — around 24 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (July, 11 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateApr 924 µg/m³Jul 2211 µg/m³
PM2.5 (µg/m³)Level
Jan17Moderate
Feb20Moderate
Mar24Moderate
Apr24Moderate
May21Moderate
Jun16Moderate
Jul11Good
Aug11Good
Sep12Good
Oct11Good
Nov14Moderate
Dec13Moderate
Location & terrain

Where is Karatsu?

Karatsu sits at 33.4°N, 130.0°E, 7 m above sea level, in Japan. The nearest listed city is Imarichō-kō, 21 km away.

Topography around Karatsu

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

Within 3 km, the terrain around Karatsu has only modest variations in elevation — a maximum elevation change of 218 m around an average of 38 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 899 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,318 m.

The land around Karatsu is covered by trees (41%), artificial surfaces (28%) and water (24%) within 3 km, trees (59%) and water (29%) within 16 km, and water (58%) and trees (29%) within 80 km.

3 km
218 m
16 km
899 m
80 km
1,318 m
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Imarichō-kō 21 km · Taku 23 km · Itoshima 23 km · Maebaru-chūō 25 km · Ogi 28 km · Matsuura 28 km · Takeo 28 km · Arita 30 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 Karatsu (33.4425°, 129.9697°, elevation 7 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).