Rock Springs weather in December

In December, Rock Springs sees average daytime highs of 27°F and overnight lows near 10°F, with 0.7 in of precipitation across 5.7 wet days and about 9 hours of daylight. It is the 11th-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 31°F in the first days to 25°F by the end. The sky is clear or mostly clear about 28% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 12 min at the start of December to 9 hours by month's end. Set against the rest of the year, December is Rock Springs's 11th-clearest and 10th-windiest month. For the whole year in context, see Rock Springs's year-round climate.

Daytime high
27°
11th warmest
Overnight low
10°
2nd coldest
Precipitation
0.7 in
5.7 wet days
Daylight
9 hours
7:43 AM – 4:43 PM
Cloud cover
60%
11th clearest
Wind
7 mph
10th windiest
Solar energy
2.29 kWh/m²
Travel score
0.0
out of 10

Rock Springs is city in Sweetwater County, Wyoming, United States.

Density
478/km²
people per km²
Founded
1888

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 31°F in the first days to 25°F by the end.

A typical December day in Rock Springs reaches about 27°F in the afternoon and slips back to 10°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 15°F and 39°F. Set against its neighbours, December runs about 12°F cooler than November and on par with January.

20°40°151015202531
Avg high (°F)Avg low (°F)
13214
23114
33113
43013
53013
63012
72912
82912
92912
102811
112811
122811
132811
142710
152710
162710
172710
182610
192610
20269
21269
22269
23259
24259
25259
26258
27258
28258
29258
30258
31258

How December really feels in Rock Springs

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
31 feel bitter (≤ 14°F)

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

Rock Springs weather by month

How December compares with the rest of the year at a glance. December is the 11th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan26° / 10°0.75.56.19.30.0
Feb30° / 13°0.75.25.810.30.0
Mar41° / 22°1.17.16.111.70.5
Apr51° / 30°1.69.86.213.12.5
May63° / 40°1.68.71.814.35.6
Jun75° / 50°0.84.50.2157.8
Jul84° / 58°0.53.8014.76.8
Aug81° / 56°0.53.9013.77.6
Sep71° / 46°0.94.80.412.37.7
Oct56° / 34°1.15.72.810.94.4
Nov39° / 20°0.85.75.19.70.3
Dec27° / 10°0.75.76.490.0

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 28% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 20% of December, with mostly cloudy or overcast conditions the remaining 53%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15248
25149
35149
45050
54951
64951
74852
84753
94753
104753
114753
124753
134753
144753
154753
164654
174753
184753
194654
204654
214654
224654
234654
244654
254654
264654
274654
284753
294852
304852
314852

Chance of precipitation in December

Any precipitationSnow

Rock Springs gets around 0.7 in of rain and snow over 5.7 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 19% and peaks near 20% on the wettest days, and about 6 days bring snow.

0%10%20%30%151015202531
Rain chance (%)Snow chance (%)
11921
21921
31921
41921
51821
61821
71821
81821
91821
101921
111921
121922
131922
141922
151922
162022
172022
182022
192022
202022
211922
221921
231921
241921
251820
261820
271820
281819
291819
301819
311719

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 7 mph in December.

Across December, daily wind ranges from about 7 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
18light breeze
28light breeze
37light breeze
47light breeze
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
317light breeze

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 12 min at the start of December to 9 hours by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 12 minutes over December. Sunrise moves from 7:30 AM to 7:49 AM, and sunset from 4:43 PM to 4:51 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.27:304:43
29.27:314:43
39.27:324:42
49.27:334:42
59.17:344:42
69.17:354:42
79.17:364:42
89.17:374:42
99.17:384:42
109.17:394:42
119.07:394:42
129.07:404:42
139.07:414:42
149.07:424:43
159.07:424:43
169.07:434:43
179.07:444:43
189.07:444:44
199.07:454:44
209.07:454:44
219.07:464:45
229.07:464:45
239.07:474:46
249.07:474:46
259.07:484:47
269.07:484:47
279.07:484:48
289.07:494:49
299.07:494:49
309.07:494:50
319.07:494:51

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.29 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.29 kWh/m² to a high of 8.01 kWh/m² in June across the year — December's 2.29 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.4Moderate
22.4Moderate
32.4Moderate
42.4Moderate
52.3Moderate
62.3Moderate
72.3Moderate
82.3Moderate
92.3Moderate
102.3Moderate
112.3Moderate
122.3Moderate
132.3Moderate
142.3Moderate
152.3Moderate
162.3Moderate
172.3Moderate
182.3Moderate
192.3Moderate
202.3Moderate
212.3Moderate
222.3Moderate
232.3Moderate
242.3Moderate
252.3Moderate
262.3Moderate
272.3Moderate
282.4Moderate
292.4Moderate
302.4Moderate
312.4Moderate
Planning a trip in December

Is December a good time to visit Rock Springs?

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 Rock Springs.

What to pack for Rock Springs in December

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

In December, Rock Springs sees daytime highs around 27°F and nights near 10°F. Pack a warm layer and a heavy coat. About 6 days see rain.

a warm layera heavy coat

UV index in Rock Springs 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 Rock Springs peaks around July 16 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 highExtremeVery highHighModerateJul 16UV 11Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb4Moderate
Mar6High
Apr5High
May8Very high
Jun10Very high
Jul11Extreme
Aug9Very high
Sep7Very high
Oct5Moderate
Nov3Moderate
Dec2Low
Location & terrain

Where is Rock Springs?

Rock Springs sits at 41.6°N, 109.2°W, 6,388 ft above sea level, in United States. The nearest listed city is Park City, 136 mi away.

Topography around Rock Springs

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

Within 2 miles, the terrain around Rock Springs has only modest variations in elevation — a maximum elevation change of 581 ft around an average of 6,437 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,841 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,213 ft.

The land around Rock Springs is covered by shrubs (37%), bare terrain (25%) and artificial surfaces (21%) within 2 miles, shrubs (48%) and bare terrain (29%) within 10 miles, and shrubs (46%), bare terrain (26%) and grassland (25%) within 50 miles.

2 miles
581 ft
10 miles
1,841 ft
50 miles
4,213 ft
treesshrubsgrasslandartificial surfacesbare terrainwater
December weather nearby: Park City 136 mi · Logan 136 mi · Conda 143 mi · North Ogden 144 mi · Brigham City 145 mi · Farmington 145 mi · Ogden 146 mi · South Ogden 146 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 Rock Springs (41.5875°, -109.2029°, elevation 6,388 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).