Arlington weather in December

In December, Arlington sees average daytime highs of 43°F and overnight lows near 35°F, with 9.3 in of precipitation across 19.2 wet days and about 8.2 hours of daylight. It is the 12th-warmest and 3rd-wettest month of the year here.

Day-to-day highs hold fairly steady near 43°F through the month. The sky is clear or mostly clear about 13% of the time in December, and the air most often feels dry.

Daylight stretches from about 8 h 24 min at the start of December to 8 h 12 min by month's end. Set against the rest of the year, December is Arlington's 12th-clearest and 1st-windiest month. For the whole year in context, see Arlington's year-round climate.

Daytime high
43°
12th warmest
Overnight low
35°
1st coldest
Precipitation
9.3 in
19.2 wet days
Daylight
8 h 12 min
8:00 AM – 4:09 PM
Cloud cover
77%
12th clearest
Wind
6 mph
1st windiest
Solar energy
0.83 kWh/m²
Travel score
0.4
out of 10

Arlington is city in northern Snohomish County, Washington, United States.

Density
790/km²
people per km²
Founded
1903

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 43°F through the month.

A typical December day in Arlington reaches about 43°F in the afternoon and slips back to 35°F overnight — a 8°F spread between the day's warmth and the night's chill. On most days the high lands between 37°F and 49°F. Set against its neighbours, December runs about 5°F cooler than November and on par with January.

20°30°40°50°60°151015202531
Avg high (°F)Avg low (°F)
14436
24435
34435
44435
54435
64435
74435
84435
94435
104335
114335
124335
134335
144335
154335
164335
174335
184335
194335
204335
214335
224335
234335
244335
254335
264335
274335
284335
294335
304335
314335

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 12th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan44° / 36°9.319.15.38.60.6
Feb47° / 36°6.115.54.59.91.2
Mar51° / 38°7.619.63.711.61.9
Apr56° / 42°5.616.4113.43.2
May62° / 47°3.812.10.114.95.0
Jun66° / 51°2.89.8015.86.0
Jul72° / 55°1.35.2015.57.8
Aug73° / 55°1.65.5014.17.8
Sep67° / 50°3.48.8012.46.5
Oct57° / 44°7.214.9010.63.7
Nov48° / 38°10.419.22.291.4
Dec43° / 35°9.319.26.18.20.4

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 13% of the time in December, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 9% of December, with mostly cloudy or overcast conditions the remaining 78%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12575
22575
32674
42674
52674
62575
72575
82575
92476
102278
112278
122179
132179
142080
152080
162080
171981
181981
192080
202080
212080
222080
232080
242179
252179
262278
272377
282278
292278
302377
312377

Chance of precipitation in December

Any precipitationSnow

Arlington gets around 9.3 in of rain and snow over 19.2 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 63% and peaks near 66% on the wettest days, and about 6 days bring snow.

0%20%40%60%80%151015202531
Rain chance (%)Snow chance (%)
16115
26115
36115
46115
56115
66115
76116
86216
96216
106316
116317
126417
136518
146619
156619
166620
176621
186621
196522
206522
216523
226423
236423
246323
256323
266223
276222
286222
296222
306321
316321

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 6 mph in December, the windiest month of the year.

Across December, daily wind ranges from about 6 mph on the calmest days to 6 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 8 h 24 min at the start of December to 8 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 7:45 AM to 8:06 AM, and sunset from 4:11 PM to 4:17 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
18.47:454:11
28.47:464:11
38.47:484:10
48.47:494:10
58.37:504:10
68.37:514:10
78.37:524:09
88.37:534:09
98.27:544:09
108.27:554:09
118.27:564:09
128.27:574:09
138.27:584:09
148.27:584:09
158.27:594:09
168.28:004:09
178.28:014:10
188.18:014:10
198.18:024:10
208.18:024:11
218.18:034:11
228.18:034:11
238.18:044:12
248.18:044:12
258.18:054:13
268.18:054:14
278.28:054:14
288.28:064:15
298.28:064:16
308.28:064:17
318.28:064:17

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 0.83 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 0.83 kWh/m² to a high of 6.16 kWh/m² in July across the year — December's 0.83 kWh/m² sits near the bottom.

00.511.52151015202531
Solar energy (kWh/m²)Level
10.9Dim
20.9Dim
30.9Dim
40.9Dim
50.9Dim
60.9Dim
70.8Dim
80.8Dim
90.8Dim
100.8Dim
110.8Dim
120.8Dim
130.8Dim
140.8Dim
150.8Dim
160.8Dim
170.8Dim
180.8Dim
190.8Dim
200.8Dim
210.8Dim
220.8Dim
230.8Dim
240.8Dim
250.8Dim
260.8Dim
270.8Dim
280.8Dim
290.8Dim
300.9Dim
310.9Dim
Planning a trip in December

Hazard calendar for Arlington

In seasonPeak

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

Arlington's rainy season runs October–April, when most of the year's rain falls.

Rainy season
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).

0.4
Sightseeing
12th-best month of the year
0.0
Beach & pool
8th-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 43°F and nights near 35°F. Pack a warm layer and rain gear. Worth having: a heavy coat. About 19 days see rain.

a warm layerrain geara heavy coat

Sea temperature near Arlington in December

The nearest coast averages about 47°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 35 mi away) is warmest in August at about 53°F and coldest in February near 46°F.

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

45°50°55°JanFebMarAprMayJunJulAugSepOctNovDecbracing
Sea temperature (°F)Comfort
Jan46Bracing
Feb46Bracing
Mar47Bracing
Apr48Bracing
May50Bracing
Jun52Bracing
Jul53Bracing
Aug53Bracing
Sep53Bracing
Oct50Bracing
Nov49Bracing
Dec47Bracing

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 17 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 18 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 17UV 8Dec 18UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar4Moderate
Apr5Moderate
May7High
Jun6High
Jul8Very high
Aug6High
Sep4Moderate
Oct3Moderate
Nov1Low
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 August — around 20 µg/m³ PM2.5 (moderate), about 3.1× the cleanest month (December, 6 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodGoodModerateGoodModerateGoodAug 2119 µg/m³Dec 157 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb10Good
Mar12Moderate
Apr12Good
May13Moderate
Jun11Good
Jul10Good
Aug20Moderate
Sep18Moderate
Oct11Good
Nov7Good
Dec6Good
Location & terrain

Where is Arlington?

Arlington sits at 48.2°N, 122.1°W, 115 ft above sea level, in United States. The nearest listed city is Marysville, 11 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 479 ft around an average of 157 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 3,297 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 10,755 ft.

The land around Arlington is covered by trees (51%) and grassland (32%) within 2 miles, trees (76%) within 10 miles, and trees (66%) and water (21%) within 50 miles.

2 miles
479 ft
10 miles
3,297 ft
50 miles
10,755 ft
treesgrasslandcroplandartificial surfacesbare terrainsnow and icewater
December weather nearby: Marysville 11 mi · Lake Stevens 13 mi · West Lake Stevens 14 mi · Everett 16 mi · Mount Vernon 18 mi · Mukilteo 19 mi · Eastmont 21 mi · Silver Firs 23 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 (48.1987°, -122.1251°, elevation 115 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. 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).