Arlington weather in December

In December, Arlington sees average daytime highs of 40°F and overnight lows near 27°F, with 4.2 in of precipitation across 10.3 wet days and about 9 hours of daylight. It is the 10th-warmest and 2nd-wettest month of the year here.

Highs ease over the month, from about 44°F in the first days to 38°F by the end. The sky is clear or mostly clear about 31% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 06 min at the start of December to 8 h 54 min by month's end. Set against the rest of the year, December is Arlington's 7th-clearest and 4th-windiest month. For the whole year in context, see Arlington's year-round climate.

Daytime high
40°
10th warmest
Overnight low
27°
3rd coldest
Precipitation
4.2 in
10.3 wet days
Daylight
8 h 54 min
7:14 AM – 4:08 PM
Cloud cover
59%
7th clearest
Wind
8 mph
4th windiest
Solar energy
1.59 kWh/m²
Travel score
0.2
out of 10

Arlington is town in Middlesex County, Massachusetts, United States.

Founded
1630

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 44°F in the first days to 38°F by the end.

A typical December day in Arlington reaches about 40°F in the afternoon and slips back to 27°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 29°F and 53°F. Set against its neighbours, December runs about 10°F cooler than November and about 5°F warmer than January.

20°40°60°151015202531
Avg high (°F)Avg low (°F)
14531
24431
34430
44430
54329
64329
74229
84228
94228
104128
114128
124127
134027
144027
154027
164026
174026
183926
193926
203926
213926
223926
233925
243825
253825
263825
273824
283824
293824
303724
313724

How December really feels in Arlington

Once humidity and wind are folded in, December averages 0 days that feel above 90°F and 31 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
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.

Arlington weather by month

How December compares with the rest of the year at a glance. December is the 10th-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan35° / 21°3.39.66.29.30.0
Feb38° / 22°3.08.65.710.30.0
Mar45° / 30°4.2114.911.61.0
Apr57° / 40°3.710.61.213.13.9
May67° / 49°3.110.5014.46.0
Jun76° / 59°3.410.70156.5
Jul82° / 65°3.110.3014.86.1
Aug80° / 63°3.49.5013.76.6
Sep73° / 56°3.38.3012.37.0
Oct62° / 45°3.89.50.210.85.3
Nov50° / 35°3.49.31.19.62.3
Dec40° / 27°4.210.34.790.2

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 31% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 15% of December, with mostly cloudy or overcast conditions the remaining 53%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14852
24852
34852
44852
54753
64753
74753
84654
94654
104555
114654
124555
134555
144555
154357
164357
174357
184456
194555
204654
214654
224654
234753
244852
254852
264951
274951
285050
295050
305050
315050

Chance of precipitation in December

Any precipitationSnow

Arlington gets around 4.2 in of rain and snow over 10.3 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 33% and peaks near 34% on the wettest days, and about 5 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
13111
23112
33212
43213
53214
63214
73215
83315
93316
103416
113416
123416
133416
143416
153416
163415
173415
183415
193414
203414
213314
223315
233315
243315
253315
263215
273215
283216
293216
303216
313217

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 8 mph in December.

Across December, daily wind ranges from about 8 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (mph)Feels
18light breeze
28light breeze
38light breeze
48light breeze
58light breeze
68light breeze
78light breeze
88light breeze
98light breeze
108light breeze
118light breeze
128light breeze
138light breeze
148light breeze
158light breeze
168light breeze
178light breeze
188light breeze
198light breeze
208light breeze
218light breeze
228light breeze
238light breeze
248light breeze
258light breeze
268light breeze
278light breeze
288light breeze
298light breeze
308light breeze
318light breeze

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 06 min at the start of December to 8 h 54 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 7:01 AM to 7:20 AM, and sunset from 4:08 PM to 4:16 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.17:014:08
29.17:024:08
39.17:034:08
49.17:044:07
59.07:054:07
69.07:064:07
79.07:064:07
89.07:074:07
99.07:084:07
109.07:094:07
119.07:104:07
128.97:114:07
138.97:114:07
148.97:124:08
158.97:134:08
168.97:144:08
178.97:144:08
188.97:154:09
198.97:154:09
208.97:164:09
218.97:164:10
228.97:174:10
238.97:174:11
248.97:184:11
258.97:184:12
268.97:194:12
278.97:194:13
288.97:194:14
298.97:194:14
308.97:204:15
318.97:204:16

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 1.59 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 1.59 kWh/m² to a high of 5.9 kWh/m² in July across the year — December's 1.59 kWh/m² sits near the bottom.

00.511.522.5151015202531
Solar energy (kWh/m²)Level
11.7Dim
21.7Dim
31.7Dim
41.7Dim
51.6Dim
61.6Dim
71.6Dim
81.6Dim
91.6Dim
101.6Dim
111.6Dim
121.6Dim
131.6Dim
141.6Dim
151.6Dim
161.6Dim
171.6Dim
181.6Dim
191.6Dim
201.6Dim
211.6Dim
221.6Dim
231.6Dim
241.6Dim
251.6Dim
261.6Dim
271.6Dim
281.6Dim
291.6Dim
301.6Dim
311.7Dim
Planning a trip in December

Hazard calendar for Arlington

In seasonPeak

None of Arlington's seasonal hazards are active in December. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Arlington sits in the Atlantic hurricane belt; the season peaks August–October.

Atlantic hurricane
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is December a good time to visit Arlington?

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

0.2
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 Arlington.

What to pack for Arlington in December

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

In December, Arlington sees daytime highs around 40°F and nights near 27°F. Pack a warm layer and a heavy coat. Worth having: rain gear. About 10 days see rain.

a warm layera heavy coatrain gear

Sea temperature near Arlington in December

The nearest coast averages about 46°F 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 15 mi away) is warmest in August at about 66°F and coldest in February near 38°F.

The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.

40°50°60°70°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°F)Comfort
Jan41Bracing
Feb38Bracing
Mar38Bracing
Apr42Bracing
May50Bracing
Jun58Bracing
Jul65Cool
Aug66Cool
Sep63Cool
Oct56Bracing
Nov50Bracing
Dec46Bracing

UV index in Arlington in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 1. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Arlington peaks around July 10 at about 7 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near January 1 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighHighModerateLowJul 10UV 7Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb3Moderate
Mar4Moderate
Apr5High
May7Very high
Jun7Very high
Jul7Very high
Aug5Moderate
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Arlington 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 Arlington is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (November, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1715 µg/m³Nov 188 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb13Moderate
Mar13Moderate
Apr13Moderate
May14Moderate
Jun13Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct9Good
Nov8Good
Dec9Good
Location & terrain

Where is Arlington?

Arlington sits at 42.4°N, 71.2°W, 66 ft above sea level, in United States. The nearest listed city is Belmont, 1.9 mi away.

Topography around Arlington

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Arlington.

Within 2 miles, the terrain around Arlington has only modest variations in elevation — a maximum elevation change of 384 ft around an average of 115 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 486 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,329 ft.

The land around Arlington is covered by trees (58%) and artificial surfaces (31%) within 2 miles, trees (59%) and artificial surfaces (28%) within 10 miles, and trees (65%) and water (26%) within 50 miles.

2 miles
384 ft
10 miles
486 ft
50 miles
2,329 ft
treesgrasslandartificial surfaceswaterwetland
December weather nearby: Belmont 1.9 mi · Medford 2.5 mi · Winchester 2.5 mi · Watertown 3.1 mi · Somerville 3.7 mi · Cambridge 3.7 mi · Lexington 4.3 mi · Allston 4.3 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

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 Arlington (42.4154°, -71.1564°, elevation 66 ft), 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).