Nagai weather in December

In December, Nagai sees average daytime highs of 3°C and overnight lows near -3°C, with 181 mm of precipitation across 23.2 wet days and about 9.4 hours of daylight. It is the 10th-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 5°C in the first days to 1°C by the end. The sky is clear or mostly clear about 6% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 30 min at the start of December to 9 h 24 min by month's end. Set against the rest of the year, December is Nagai's 10th-clearest and 4th-windiest month. For the whole year in context, see Nagai's year-round climate.

Daytime high
10th warmest
Overnight low
-3°
3rd coldest
Precipitation
181 mm
23.2 wet days
Daylight
9 h 24 min
6:55 AM – 4:17 PM
Cloud cover
77%
10th clearest
Wind
10 km/h
4th windiest
Solar energy
1.82 kWh/m²
Travel score
0.0
out of 10

Nagai is city in Yamagata Prefecture, Japan.

Density
145/km²
people per km²
Founded
1954

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 5°C in the first days to 1°C by the end.

A typical December day in Nagai reaches about 3°C in the afternoon and slips back to -3°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between -1°C and 7°C. Set against its neighbours, December runs about 6°C cooler than November and about 3°C warmer than January.

-10°-5°10°15°151015202531
Avg high (°C)Avg low (°C)
160
26-1
36-1
45-1
55-1
65-1
75-2
84-2
94-2
104-2
114-2
124-2
133-2
143-3
153-3
163-3
173-3
183-3
193-3
202-3
212-3
222-3
232-3
242-3
252-4
262-4
272-4
282-4
291-4
301-4
311-4

How December really feels in Nagai

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.

Nagai weather by month

How December compares with the rest of the year at a glance. December is the 10th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -5°19024.425.29.70.0
Feb / -5°13720.620.510.50.0
Mar / -2°14619.415.611.70.2
Apr11° / 11515.14.4132.5
May18° / 11614.20.1145.1
Jun22° / 14°15515.2014.65.4
Jul25° / 18°24119.9014.45.1
Aug26° / 19°18317.4013.55.4
Sep22° / 15°15515.3012.35.5
Oct16° / 13914.30.1114.5
Nov10° / 13417.55.59.91.7
Dec / -3°18123.219.29.40.0

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 6% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 11% of December, with mostly cloudy or overcast conditions the remaining 83%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12377
22179
32179
42179
52080
62080
71981
81981
91981
101981
111882
121882
131882
141783
151783
161783
171783
181783
191684
201684
211684
221684
231684
241585
251585
261585
271486
281486
291486
301486
311486

Chance of precipitation in December

Any precipitationSnow

Nagai gets around 181 mm of rain and snow over 23.2 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 74% and peaks near 78% on the wettest days, and about 19 days bring snow. The odds climb toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)Snow chance (%)
16842
26844
36946
47048
57150
67251
77353
87455
97457
107558
117559
127560
137661
147562
157563
167563
177564
187564
197565
207566
217566
227567
237568
247569
257670
267670
277671
287772
297774
307875
317876

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 10 km/h in December.

Across December, daily wind ranges from about 9 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
19calm
29calm
39calm
49calm
59calm
69calm
79calm
89calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1810calm
1910calm
2010calm
2110calm
2210calm
2310calm
2411calm
2511calm
2611calm
2711calm
2811calm
2911calm
3011calm
3111calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 30 min at the start of December to 9 h 24 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 6:43 AM to 7:01 AM, and sunset from 4:16 PM to 4:25 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.56:434:16
29.56:444:16
39.56:454:16
49.56:464:16
59.56:474:16
69.56:484:16
79.56:484:16
89.46:494:16
99.46:504:16
109.46:514:16
119.46:524:16
129.46:524:16
139.46:534:16
149.46:544:16
159.46:544:17
169.46:554:17
179.46:564:17
189.46:564:18
199.46:574:18
209.46:574:18
219.46:584:19
229.36:584:19
239.46:594:20
249.46:594:20
259.47:004:21
269.47:004:21
279.47:004:22
289.47:014:23
299.47:014:23
309.47:014:24
319.47:014:25

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 1.82 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 1.82 kWh/m² to a high of 5.35 kWh/m² in May across the year — December's 1.82 kWh/m² sits near the bottom.

00.511.522.5151015202531
Solar energy (kWh/m²)Level
11.8Dim
21.8Dim
31.8Dim
41.8Dim
51.8Dim
61.8Dim
71.8Dim
81.8Dim
91.8Dim
101.8Dim
111.8Dim
121.8Dim
131.8Dim
141.8Dim
151.8Dim
161.8Dim
171.8Dim
181.8Dim
191.9Dim
201.9Dim
211.9Dim
221.9Dim
231.9Dim
241.9Dim
251.9Dim
261.9Dim
271.9Dim
282.0Dim
292.0Dim
302.0Dim
312.0Dim
Planning a trip in December

Hazard calendar for Nagai

In seasonPeak

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

Nagai 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 Nagai?

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

0.0
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 Nagai.

What to pack for Nagai in December

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

In December, Nagai sees daytime highs around 3°C and nights near -3°C. Pack a warm layer and rain gear. Worth having: a heavy coat. About 23 days see rain.

a warm layerrain geara heavy coat

Sea temperature near Nagai in December

The nearest coast averages about 15°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 58 km away) is warmest in August at about 26°C and coldest in March near 9°C.

It's comfortable for a long swim from Jun 21 to Oct 29 — about 4.3 months when the water holds above 20°C.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan12Bracing
Feb10Bracing
Mar9Bracing
Apr11Bracing
May15Bracing
Jun20Cool
Jul23Refreshing
Aug26Warm
Sep25Warm
Oct22Refreshing
Nov18Cool
Dec15Bracing

UV index in Nagai 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 Nagai peaks around August 12 at about 10 (very high) — 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 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateAug 12UV 10Jan 1UV 2
UV index (midday)Level
Jan2Moderate
Feb3Moderate
Mar5Moderate
Apr7High
May8Very high
Jun8Very high
Jul9Very high
Aug10Very high
Sep8Very high
Oct5High
Nov3Moderate
Dec2Moderate

Air quality in Nagai 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 Nagai is worst in April — around 22 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (December, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodApr 1622 µg/m³Dec 1710 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar21Moderate
Apr22Moderate
May21Moderate
Jun16Moderate
Jul14Moderate
Aug12Moderate
Sep12Good
Oct12Good
Nov11Good
Dec10Good
Location & terrain

Where is Nagai?

Nagai sits at 38.1°N, 140.0°E, 204 m above sea level, in Japan. The nearest listed city is Nanyō, 10 km away.

Topography around Nagai

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

Within 3 km, the terrain around Nagai has significant variations in elevation — a maximum elevation change of 254 m around an average of 224 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,329 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,110 m.

The land around Nagai is covered by cropland (41%), trees (28%) and artificial surfaces (24%) within 3 km, trees (72%) and cropland (21%) within 16 km, and trees (74%) within 80 km.

3 km
254 m
16 km
1,329 m
80 km
2,110 m
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Nanyō 10 km · Takahata 18 km · Kaminoyama 22 km · Yonezawa 23 km · Yamagata 32 km · Sagae 36 km · Tendō 40 km · Yachi 43 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 Nagai (38.1036°, 140.035°, elevation 204 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).