Hachimantai weather in December

In December, Hachimantai sees average daytime highs of 2°C and overnight lows near -5°C, with 74 mm of precipitation across 12 wet days and about 9.2 hours of daylight. It is the 10th-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 4°C in the first days to 0°C by the end. The sky is clear or mostly clear about 12% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 24 min at the start of December to 9 h 12 min by month's end. Set against the rest of the year, December is Hachimantai's 5th-clearest and 2nd-windiest month. For the whole year in context, see Hachimantai's year-round climate.

Daytime high
10th warmest
Overnight low
-5°
3rd coldest
Precipitation
74 mm
12 wet days
Daylight
9 h 12 min
6:56 AM – 4:07 PM
Cloud cover
69%
5th clearest
Wind
11 km/h
2nd windiest
Solar energy
1.87 kWh/m²
Travel score
0.0
out of 10

Hachimantai is city in Iwate Prefecture, Japan.

Density
29/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 4°C in the first days to 0°C by the end.

A typical December day in Hachimantai reaches about 2°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 -3°C and 6°C. Set against its neighbours, December runs about 6°C cooler than November and about 3°C warmer than January.

-15°-10°-5°10°151015202531
Avg high (°C)Avg low (°C)
15-2
24-2
34-3
44-3
54-3
63-3
73-3
83-4
93-4
103-4
112-4
122-4
132-5
142-5
152-5
162-5
171-5
181-5
191-6
201-6
211-6
221-6
231-6
241-6
251-6
260-6
270-7
280-7
290-7
300-7
310-7

How December really feels in Hachimantai

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
14 feel bitter (≤ -10°C)

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

Hachimantai 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-1° / -9°6010.513.29.50.0
Feb / -8°5910.412.110.40.0
Mar / -4°9014.212.111.70.2
Apr11° / 9014.14132.6
May17° / 9312.70.314.25.1
Jun21° / 13°10512.8014.85.7
Jul24° / 17°14416.4014.55.6
Aug25° / 18°14114.9013.65.9
Sep21° / 14°13812.9012.35.8
Oct15° / 11111.20.110.94.5
Nov / 7612.849.81.4
Dec / -5°7412129.20.0

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 12% 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 66%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13862
23664
33664
43664
53664
63664
73565
83565
93664
103565
113565
123565
133565
143466
153466
163466
173466
183466
193466
203367
213367
223367
233466
243367
253367
263367
273367
283367
293466
303367
313367

Chance of precipitation in December

Any precipitationSnow

Hachimantai gets around 74 mm of rain and snow over 12 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 39% and peaks near 43% on the wettest days, and about 12 days bring snow. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202531
Rain chance (%)Snow chance (%)
14330
24331
34332
44233
54234
64235
74135
84136
94137
104137
114038
124038
134038
144039
154039
164039
173940
183940
193940
203941
213841
223841
233841
243742
253742
263642
273642
283642
293543
303543
313443

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 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 24 min at the start of December to 9 h 12 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 6:44 AM to 7:02 AM, and sunset from 4:07 PM to 4:15 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.46:444:07
29.46:454:06
39.36:464:06
49.36:474:06
59.36:484:06
69.36:494:06
79.36:494:06
89.36:504:06
99.26:514:06
109.26:524:06
119.26:534:06
129.26:534:06
139.26:544:06
149.26:554:07
159.26:554:07
169.26:564:07
179.26:574:07
189.26:574:08
199.26:584:08
209.26:584:09
219.26:594:09
229.26:594:09
239.27:004:10
249.27:004:10
259.27:014:11
269.27:014:12
279.27:014:12
289.27:024:13
299.27:024:13
309.27:024:14
319.27:024:15

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 1.87 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 1.87 kWh/m² to a high of 5.27 kWh/m² in May across the year — December's 1.87 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
11.9Dim
21.9Dim
31.9Dim
41.9Dim
51.9Dim
61.9Dim
71.9Dim
81.9Dim
91.9Dim
101.9Dim
111.9Dim
121.9Dim
131.9Dim
141.9Dim
151.9Dim
161.9Dim
171.9Dim
181.9Dim
191.9Dim
201.9Dim
211.9Dim
221.9Dim
231.9Dim
242.0Dim
252.0Dim
262.0Dim
272.0Moderate
282.0Moderate
292.0Moderate
302.1Moderate
312.1Moderate
Planning a trip in December

Is December a good time to visit Hachimantai?

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
8th-best month of the year

December is a weaker month for outdoor sightseeing in Hachimantai.

What to pack for Hachimantai in December

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

In December, Hachimantai sees daytime highs around 2°C and nights near -5°C. Pack a warm layer and a heavy coat. Worth having: rain gear. About 12 days see rain.

a warm layera heavy coatrain gear

Sea temperature near Hachimantai in December

The nearest coast averages about 12°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 68 km away) is warmest in August at about 21°C and coldest in March near 6°C.

It's comfortable for a long swim from Aug 8 to Sep 25 — about 1.6 months when the water holds above 20°C.

5°10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarm
Sea temperature (°C)Comfort
Jan10Bracing
Feb8Bracing
Mar6Bracing
Apr7Bracing
May10Bracing
Jun14Bracing
Jul18Cool
Aug21Refreshing
Sep21Refreshing
Oct18Cool
Nov15Cool
Dec12Bracing

UV index in Hachimantai 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 Hachimantai peaks around August 18 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighVery highHighModerateLowAug 18UV 9Jan 1UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May8Very high
Jun8Very high
Jul6High
Aug9Very high
Sep7High
Oct5Moderate
Nov2Moderate
Dec2Low

Air quality in Hachimantai 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 Hachimantai is worst in April — around 20 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (December, 9 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1420 µg/m³Dec 1610 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar19Moderate
Apr20Moderate
May19Moderate
Jun14Moderate
Jul12Moderate
Aug11Good
Sep11Good
Oct12Good
Nov11Good
Dec9Good
Location & terrain

Where is Hachimantai?

Hachimantai sits at 39.9°N, 141.1°E, 228 m above sea level, in Japan. The nearest listed city is Takizawa, 11 km away.

Topography around Hachimantai

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

Within 3 km, the terrain around Hachimantai has only modest variations in elevation — a maximum elevation change of 149 m around an average of 245 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,870 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,117 m.

The land around Hachimantai is covered by cropland (46%) and trees (38%) within 3 km, trees (75%) within 16 km, and trees (84%) within 80 km.

3 km
149 m
16 km
1,870 m
80 km
2,117 m
treesgrasslandcroplandartificial surfaceswater
December weather nearby: Takizawa 11 km · Morioka 22 km · Shizukuishi 26 km · Yahaba 32 km · Semboku 39 km · Hizume 39 km · Hanawa 43 km · Ninohe 46 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 Hachimantai (39.8998°, 141.1299°, elevation 228 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. 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).