Gaithersburg weather in December

In December, Gaithersburg sees average daytime highs of 45°F and overnight lows near 32°F, with 3.5 in of precipitation across 8.8 wet days and about 9.3 hours of daylight. It is the 10th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 48°F in the first days to 43°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 30 min at the start of December to 9 h 18 min by month's end. Set against the rest of the year, December is Gaithersburg's 6th-clearest and 5th-windiest month. For the whole year in context, see Gaithersburg's year-round climate.

Daytime high
45°
10th warmest
Overnight low
32°
3rd coldest
Precipitation
3.5 in
8.8 wet days
Daylight
9 h 18 min
7:27 AM – 4:43 PM
Cloud cover
60%
6th clearest
Wind
7 mph
5th windiest
Solar energy
1.91 kWh/m²
Travel score
1.1
out of 10

Gaithersburg is city in Montgomery County, Maryland, United States; suburb of Washington, D.C..

Density
2,518/km²
people per km²
Founded
1802

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 48°F in the first days to 43°F by the end.

A typical December day in Gaithersburg reaches about 45°F in the afternoon and slips back to 32°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 33°F and 58°F. Set against its neighbours, December runs about 10°F cooler than November and about 4°F warmer than January.

20°40°60°151015202531
Avg high (°F)Avg low (°F)
14935
24934
34934
44834
54834
64733
74733
84733
94633
104632
114632
124532
134532
144532
154531
164531
174431
184431
194431
204431
214431
224430
234430
244430
254430
264330
274330
284330
294330
304330
314329

How December really feels in Gaithersburg

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.

Gaithersburg weather by month

How December compares with the rest of the year at a glance. December is the 10th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan41° / 27°3.18.63.19.60.1
Feb44° / 29°2.88.43.210.50.8
Mar53° / 36°3.810.22.311.73.0
Apr65° / 46°3.410.40.2135.7
May73° / 55°3.811.5014.16.5
Jun83° / 64°3.610.8014.75.7
Jul87° / 69°4.011.3014.54.6
Aug85° / 67°3.410.5013.55.3
Sep78° / 60°4.59.3012.36.9
Oct66° / 49°3.47.80116.4
Nov55° / 38°3.07.70.39.93.7
Dec45° / 32°3.58.81.99.31.1

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 14% of December, with mostly cloudy or overcast conditions the remaining 54%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14654
24654
34654
44654
54555
64456
74456
84456
94456
104357
114357
124357
134456
144456
154456
164555
174555
184555
194654
204654
214753
224654
234753
244753
254852
264753
274753
284753
294654
304654
314654

Chance of precipitation in December

Any precipitationSnow

Gaithersburg gets around 3.5 in of rain and snow over 8.8 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 29% and peaks near 30% on the wettest days, and about 2 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1303
2304
3304
4304
5305
6305
7306
8306
9306
10307
11307
12307
13307
14307
15307
16307
17297
18297
19297
20287
21287
22276
23276
24266
25266
26266
27266
28266
29266
30266
31277

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
2973
3982
4982
5982
6982
7982
8991
9991
10991
11991
12991
13991
14991
15991
16991
17991
18991
19991
20991
21991
22991
23991
24991
25991
26991
27991
28991
29991
30991
31991

Wind in December

Winds average 7 mph in December.

Across December, daily wind ranges from about 7 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 30 min at the start of December to 9 h 18 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 7:15 AM to 7:33 AM, and sunset from 4:42 PM to 4:50 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.57:154:42
29.47:164:42
39.47:174:42
49.47:184:42
59.47:194:42
69.47:204:42
79.47:204:41
89.37:214:42
99.37:224:42
109.37:234:42
119.37:244:42
129.37:244:42
139.37:254:42
149.37:264:42
159.37:264:43
169.37:274:43
179.37:284:43
189.37:284:43
199.27:294:44
209.27:294:44
219.27:304:45
229.27:304:45
239.27:314:46
249.27:314:46
259.27:324:47
269.37:324:47
279.37:324:48
289.37:334:48
299.37:334:49
309.37:334:50
319.37:334:50

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 1.91 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 1.91 kWh/m² to a high of 6.15 kWh/m² in June across the year — December's 1.91 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.0Moderate
22.0Moderate
32.0Dim
42.0Dim
52.0Dim
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
241.9Dim
251.9Dim
261.9Dim
271.9Dim
281.9Dim
291.9Dim
301.9Dim
312.0Dim
Planning a trip in December

Is December a good time to visit Gaithersburg?

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

1.1
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 Gaithersburg.

What to pack for Gaithersburg in December

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

In December, Gaithersburg sees daytime highs around 45°F and nights near 32°F. Pack a warm layer. Worth having: a heavy coat and rain gear. About 9 days see rain.

a warm layera heavy coatrain gear

UV index in Gaithersburg 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 Gaithersburg peaks around July 11 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 11UV 9Dec 19UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5High
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug7High
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Gaithersburg 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 Gaithersburg is worst in July — around 17 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (November, 9 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1317 µg/m³Nov 129 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb12Moderate
Mar13Moderate
Apr13Moderate
May15Moderate
Jun16Moderate
Jul17Moderate
Aug15Moderate
Sep12Moderate
Oct9Good
Nov9Good
Dec10Good
Location & terrain

Where is Gaithersburg?

Gaithersburg sits at 39.1°N, 77.2°W, 502 ft above sea level, in United States. The nearest listed city is Montgomery Village, 2.5 mi away.

Topography around Gaithersburg

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

Within 2 miles, the terrain around Gaithersburg has only modest variations in elevation — a maximum elevation change of 259 ft around an average of 453 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 912 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,375 ft.

The land around Gaithersburg is covered by trees (52%) and artificial surfaces (34%) within 2 miles, trees (67%) within 10 miles, and trees (60%) within 50 miles.

2 miles
259 ft
10 miles
912 ft
50 miles
2,375 ft
treesgrasslandcroplandartificial surfaceswater
December weather nearby: Montgomery Village 2.5 mi · Redland 3.1 mi · Germantown 4.3 mi · Rockville 5.0 mi · North Potomac 5.6 mi · Olney 7.5 mi · North Bethesda 8.1 mi · Aspen Hill 8.1 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 Gaithersburg (39.1434°, -77.2014°, elevation 502 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. 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).