Ryōgoku weather in December

In December, Ryōgoku sees average daytime highs of 12°C and overnight lows near 5°C, with 68 mm of precipitation across 8.4 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 13°C in the first days to 10°C by the end. The sky is clear or mostly clear about 55% 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 Ryōgoku's 2nd-clearest and 11th-windiest month. For the whole year in context, see Ryōgoku's year-round climate.

Daytime high
12°
10th warmest
Overnight low
3rd coldest
Precipitation
68 mm
8.4 wet days
Daylight
9 h 36 min
6:47 AM – 4:22 PM
Cloud cover
42%
2nd clearest
Wind
11 km/h
11th windiest
Solar energy
2.32 kWh/m²
Travel score
3.2
out of 10

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 Ryōgoku reaches about 12°C in the afternoon and slips back to 5°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 8°C and 15°C. Set against its neighbours, December runs about 5°C cooler than November and about 2°C warmer than January.

-5°10°15°20°151015202531
Avg high (°C)Avg low (°C)
1147
2137
3137
4137
5137
6136
7136
8126
9126
10126
11125
12125
13125
14125
15115
16115
17114
18114
19114
20114
21114
22114
23114
24103
25103
26103
27103
28103
29103
30103
31103

How December really feels in Ryōgoku

Once humidity and wind are folded in, December averages 0 days that feel above 32°C and 2 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
2
wind chill below the day's low

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

Ryōgoku 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 / 757.60.89.92.1
Feb10° / 718.41.110.62.3
Mar13° / 12512.80.511.73.5
Apr18° / 10°11312.6012.95.3
May22° / 15°12811.6013.96.3
Jun25° / 19°15913.7014.45.8
Jul29° / 23°15013.8014.24.9
Aug30° / 24°11411.9013.44.5
Sep27° / 21°17514.3012.25.6
Oct21° / 16°20713011.16.1
Nov16° / 10°10210.4010.15.2
Dec12° / 688.40.19.63.2

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 55% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 12% of December, with mostly cloudy or overcast conditions the remaining 33%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15941
25941
36040
46040
56139
66238
76337
86337
96535
106535
116634
126634
136832
146733
156733
166832
176832
186931
196931
207030
217129
227030
237129
247129
257228
267228
277228
287327
297327
307426
317426

Chance of precipitation in December

Any precipitation

Ryōgoku gets around 68 mm of rain and snow over 8.4 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 35% on the wettest days, and about 0 day brings snow. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202531
Rain chance (%)
135
234
334
434
534
634
733
833
932
1031
1130
1229
1328
1427
1527
1626
1725
1824
1924
2023
2123
2222
2322
2421
2521
2620
2720
2820
2920
3020
3120

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
6982
7982
8991
9991
10991
11991
12991
13991
14991
151000
161000
171000
181000
191000
201000
211000
221000
231000
241000
251000
261000
271000
281000
291000
301000
311000

Wind in December

Winds average 11 km/h in December.

Across December, daily wind ranges from about 11 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
111calm
211calm
311calm
411calm
511calm
611calm
711calm
811calm
911calm
1011calm
1111calm
1211calm
1311calm
1411calm
1511calm
1611calm
1711calm
1811calm
1911calm
2011calm
2111calm
2211calm
2311calm
2411calm
2511calm
2611calm
2711calm
2811calm
2911calm
3011calm
3111calm

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 6:36 AM to 6:53 AM, and sunset from 4:21 PM to 4:30 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.86:364:21
29.76:364:21
39.76:374:21
49.76:384:21
59.76:394:21
69.76:404:21
79.76:414:21
89.76:414:21
99.66:424:21
109.66:434:21
119.66:444:21
129.66:444:21
139.66:454:22
149.66:464:22
159.66:464:22
169.66:474:22
179.66:484:23
189.66:484:23
199.66:494:24
209.66:494:24
219.66:504:24
229.66:504:25
239.66:514:25
249.66:514:26
259.66:514:26
269.66:524:27
279.66:524:28
289.66:534:28
299.66:534:29
309.66:534:29
319.66:534:30

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.32 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.32 kWh/m² to a high of 5.31 kWh/m² in May across the year — December's 2.32 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.2Moderate
22.2Moderate
32.2Moderate
42.2Moderate
52.2Moderate
62.2Moderate
72.2Moderate
82.3Moderate
92.3Moderate
102.3Moderate
112.3Moderate
122.3Moderate
132.3Moderate
142.3Moderate
152.3Moderate
162.3Moderate
172.3Moderate
182.4Moderate
192.4Moderate
202.4Moderate
212.4Moderate
222.4Moderate
232.5Moderate
242.5Moderate
252.5Moderate
262.5Moderate
272.5Moderate
282.5Moderate
292.6Moderate
302.6Moderate
312.6Moderate
Planning a trip in December

Hazard calendar for Ryōgoku

In seasonPeak

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

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

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

Is December a good time to visit Ryōgoku?

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

3.2
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 Ryōgoku.

What to pack for Ryōgoku in December

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

In December, Ryōgoku sees daytime highs around 12°C and nights near 5°C. Pack a warm layer. Worth having: rain gear. About 8 days see rain.

a warm layerrain gear

Sea temperature near Ryōgoku 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 25 km away) is warmest in August at about 25°C and coldest in February near 15°C.

It's comfortable for a long swim from Jun 5 to Nov 22 — about 5.6 months when the water holds above 20°C.

15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb15Bracing
Mar15Cool
Apr16Cool
May19Cool
Jun21Refreshing
Jul23Refreshing
Aug25Warm
Sep25Warm
Oct23Refreshing
Nov21Refreshing
Dec18Cool

UV index in Ryōgoku 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 Ryōgoku peaks around August 12 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 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 highVery highModerateAug 12UV 10Jan 1UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar4Moderate
Apr7High
May8Very high
Jun9Very high
Jul10Very high
Aug10Extreme
Sep8Very high
Oct6High
Nov3Moderate
Dec2Moderate

Air quality in Ryōgoku 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 Ryōgoku is worst in March — around 25 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (December, 14 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateMar 2425 µg/m³Dec 1914 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb18Moderate
Mar25Moderate
Apr25Moderate
May24Moderate
Jun19Moderate
Jul16Moderate
Aug15Moderate
Sep15Moderate
Oct16Moderate
Nov16Moderate
Dec14Moderate
Location & terrain

Where is Ryōgoku?

Ryōgoku sits at 35.7°N, 140.4°E, 44 m above sea level, in Japan. The nearest listed city is Narita, 9.0 km away.

Topography around Ryōgoku

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

Within 3 km, the terrain around Ryōgoku has only modest variations in elevation — a maximum elevation change of 46 m around an average of 42 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 84 m; within 80 km, large variations in elevation — a maximum elevation change of 840 m.

The land around Ryōgoku is covered by cropland (37%), trees (34%) and artificial surfaces (23%) within 3 km, trees (46%) and cropland (30%) within 16 km, and water (38%), trees (24%) and artificial surfaces (21%) within 80 km.

3 km
46 m
16 km
84 m
80 km
840 m
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Narita 9.0 km · Yachimata 9.0 km · Shisui 9.0 km · Sanmu 11 km · Sakura 12 km · Yokoshiba 13 km · Narutō 14 km · Yōkaichiba 17 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 Ryōgoku (35.7167°, 140.3667°, elevation 44 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).