Rock Springs, Wyoming climate: Normal weather by month, frost dates and records
Rock Springs's normal year runs from 13°F December nights to 84°F July afternoons, with 7.5 inches of precipitation and 54 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.5°C, December lows of −10°C, July highs of 29°C, 192 mm of precipitation a year.
- NOAA stationRock Springs Airport
- Station IDUSW00024027
- Location41.59°N 109.05°W
- Elevation6,741 ft (2,055 m)
- Population22,967
On October 23, the normal high in Rock Springs is 53°F and the normal low 31°F, and the chance of measurable rain or snow is 18%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Rock Springs.
- Jan 30° 14°
- Feb 33° 16°
- Mar 44° 24°
- Apr 53° 30°
- May 63° 38°
- Jun 75° 47°
- Jul 84° 55°
- Aug 82° 53°
- Sep 71° 44°
- Oct 56° 33°
- Nov 41° 22°
- Dec 30° 13°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Rock Springs each month?
July is the warmest month, with normal highs of 84°F; December the coldest, with normal lows of 13°F. The most precipitation falls in May (1.27 in), the least in December (0.31 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 30°F | 14°F | 21.5°F | 0.38 | 8.2 | 5 | <1 | 31 | 9 h 30 min |
| February | 33°F | 16°F | 24.3°F | 0.37 | 7.9 | 5 | <1 | 27 | 10 h 40 min |
| March | 44°F | 24°F | 34.0°F | 0.58 | 6.4 | 7 | <1 | 28 | 11 h 50 min |
| April | 53°F | 30°F | 41.2°F | 0.91 | 8.8 | 8 | <1 | 21 | 13 h 20 min |
| May | 63°F | 38°F | 50.8°F | 1.27 | 2.7 | 9 | <1 | 7 | 14 h 30 min |
| June | 75°F | 47°F | 61.0°F | 0.70 | 0.4 | 6 | 1 | 1 | 15 h 10 min |
| July | 84°F | 55°F | 69.4°F | 0.47 | 0.0 | 5 | 7 | <1 | 15 h |
| August | 82°F | 53°F | 67.3°F | 0.56 | 0.0 | 6 | 2 | <1 | 13 h 50 min |
| September | 71°F | 44°F | 57.3°F | 0.79 | 1.2 | 6 | <1 | 2 | 12 h 30 min |
| October | 56°F | 33°F | 44.5°F | 0.81 | 6.6 | 6 | <1 | 15 | 11 h 10 min |
| November | 41°F | 22°F | 31.2°F | 0.40 | 6.0 | 5 | <1 | 27 | 9 h 50 min |
| December | 30°F | 13°F | 21.4°F | 0.31 | 5.8 | 5 | <1 | 31 | 9 h 10 min |
| Year (annual) | 55°F | 32°F | 43.7°F | 7.55 | 54.0 | 72 | 10 | 189 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −1°C | −10°C | −5.8°C | 10 mm | 21 cm |
| February | 0°C | −9°C | −4.3°C | 9 mm | 20 cm |
| March | 7°C | −4°C | 1.1°C | 15 mm | 16 cm |
| April | 12°C | −1°C | 5.1°C | 23 mm | 22 cm |
| May | 17°C | 4°C | 10.4°C | 32 mm | 7 cm |
| June | 24°C | 8°C | 16.1°C | 18 mm | 1 cm |
| July | 29°C | 13°C | 20.8°C | 12 mm | 0 cm |
| August | 28°C | 12°C | 19.6°C | 14 mm | 0 cm |
| September | 22°C | 7°C | 14.1°C | 20 mm | 3 cm |
| October | 13°C | 0°C | 6.9°C | 21 mm | 17 cm |
| November | 5°C | −6°C | −0.4°C | 10 mm | 15 cm |
| December | −1°C | −10°C | −5.9°C | 8 mm | 15 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024027; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Rock Springs?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, July has the fewest days with rain (5).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024027.
When is the last frost in Rock Springs?
In Rock Springs, the last spring frost (32°F) comes after May 22 in half of years and after June 9 in one year in ten; the first autumn frost comes before September 28 in half of years and before September 14 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 221 year in 10 after June 9; 9 in 10 after May 5
- First autumn frost, half of years before
- September 281 year in 10 before September 14; 9 in 10 before October 9
NOAA puts the median frost-free season at 126 days, and the season without a hard freeze (28°F) at 149 days.
A hard freeze (28°F) comes after May 7 in half of springs and before October 5 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Rock Springs in zone 5a in ZIP code 82943, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Rock Springs's NOAA station is in zone 5b: the coldest night of a typical year reaches −14°F (29 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Wyoming · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00024027; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Rock Springs?
In a normal year in Rock Springs, 10 days a year reach 90°F, 189 nights fall to 32°F or colder and 72 days bring measurable precipitation.
- Days at 90°F or more
- 10a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 189a normal year
- Days that stay below freezing
- 62high of 32°F or less
- Days with 0.01 inch of precipitation
- 72a normal year
- Days with 1 inch of snow or more
- 17a normal year
The highest temperature in this station's record (since 1948) is 98°F, on July 13, 2002; the lowest is −37°F, on January 12, 1963.
The wettest calendar year on that record is 1965, with 14.54 in; the snowiest season is 1949–50, with 80.6 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00024027; records: ACIS (NOAA Regional Climate Centers), station USW00024027. Records use complete months only; a month missing more than three days is left out.
How humid and windy is Rock Springs, and how clear are its skies?
The summer (June-August) dew point averages 35°F. The muggiest month is July, with an average dew point of 37°F; the driest air comes in December (11°F). March is the windiest month (12.6 mph on average), and June has the most clear or nearly clear hours (83%).
| Month | Dew point | Humidity | Afternoon humidity | Wind | Clear or few clouds | Overcast |
|---|---|---|---|---|---|---|
| January | 13°F | 67% | 56% | 12.4 mph | 65% | 20% |
| February | 16°F | 62% | 47% | 12.3 mph | 64% | 18% |
| March | 20°F | 51% | 34% | 12.6 mph | 60% | 19% |
| April | 24°F | 45% | 28% | 12.5 mph | 60% | 18% |
| May | 32°F | 42% | 25% | 11.0 mph | 66% | 12% |
| June | 33°F | 30% | 17% | 10.0 mph | 83% | 3% |
| July | 37°F | 33% | 18% | 8.8 mph | 79% | 5% |
| August | 33°F | 33% | 19% | 9.1 mph | 79% | 5% |
| September | 28°F | 42% | 25% | 10.0 mph | 76% | 11% |
| October | 21°F | 52% | 36% | 11.5 mph | 67% | 19% |
| November | 14°F | 63% | 49% | 11.8 mph | 66% | 20% |
| December | 11°F | 67% | 57% | 11.9 mph | 64% | 21% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024027. Monthly averages of all hours; afternoon humidity at 3 p.m. local standard time; sky as the share of hours NOAA's observations rate clear or few clouds (a dash where NOAA publishes no sky value).
How sunny is Rock Springs?
Over a year 79% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Rock Springs, 4.7 kWh per square metre a day. September is the sunniest month (86%) and December the cloudiest (68%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 72% | 2.2 |
| February | 73% | 3.1 |
| March | 73% | 4.3 |
| April | 75% | 5.7 |
| May | 78% | 6.7 |
| June | 84% | 7.6 |
| July | 84% | 7.3 |
| August | 84% | 6.4 |
| September | 86% | 5.3 |
| October | 81% | 3.8 |
| November | 76% | 2.5 |
| December | 68% | 1.8 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Rock Springs need?
A normal year in Rock Springs brings 8,064 heating degree days, 50% more than the median U.S. place (5,373), and 319 cooling degree days, 65% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,914 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,347 | 0 |
| February | 1,139 | 0 |
| March | 961 | 0 |
| April | 712 | 0 |
| May | 442 | 2 |
| June | 159 | 39 |
| July | 21 | 159 |
| August | 38 | 109 |
| September | 242 | 11 |
| October | 637 | 0 |
| November | 1,016 | 0 |
| December | 1,350 | 0 |
| Year (annual) | 8,064 | 319 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024027. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Rock Springs been warmer than normal lately?
2025 averaged 47.4°F, 3.7°F above the 1991-2020 normal of 43.7°F. 3 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 45.4°F | +1.7°F | 4.11 | – |
| 2023 | 42.6°F | −1.1°F | 5.26 | – |
| 2024 | 45.7°F | +2.0°F | 5.87 | – |
| 2025 | 47.4°F | +3.7°F | 4.52 | – |
Over 85 complete years from 1911 to 2025, the station's annual mean temperature rose at a fitted 3.9°F per century (+0.22°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00024027; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Rock Springs's climate compare?
Rock Springs is warmer than 29 of the other 70 places with their own NOAA record in Wyoming, and wetter than 5. Across the 7,247 U.S. stations with normals, its annual mean of 43.7°F is warmer than 14%.
In the Köppen classification computed from these normals, Rock Springs is BSk: cold semi-arid steppe. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Rock Springs share this climate record?
4 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- North Rock Springs, WY2,338 people · 13 mi NW
- Reliance, WY400 people · 9 mi NW
- Superior, WY183 people · 12 mi N
- Arrowhead Springs, WY37 people · 8 mi SW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do Rock Springs's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Rock Springs. This page uses Rock Springs Airport; the other differs by site and elevation:
| Station | From this station | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Rock Springs Fire Dept USC00487847 | 10 mi W | 6,270 ft | 45.0°F | 12°F | 86°F | 10.4 | 31 | May 24 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Rock Springs's climate
What is the coldest month in Rock Springs?
December, with a normal high of 30°F and a normal low of 13°F. The warmest is July (84°F by day, 55°F at night).
Does it snow in Rock Springs?
Yes: 54 inches in a normal year, falling on 42 days with 0.1 inch or more, the most in April (8.8 inches).
What is the rainiest month in Rock Springs?
May, with 1.27 in of precipitation in a normal year; the driest is December with 0.31 in.
What plant hardiness zone is Rock Springs in?
The USDA's 2023 map puts Rock Springs in zone 5a in ZIP code 82943, the nearest ZIP area. By the same method at Rock Springs's NOAA station, the coldest night of a typical year reaches −14°F (29 years, 1991-2020): zone 5b.
How late can frost come in Rock Springs?
In half of years the last 32°F night comes after May 22; in one year in ten it comes after June 9. Waiting until June 9 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Rock Springs in OctoberThis month day by day, its records and recent years
- Wyoming climateThe statewide normals and every place in the state
- Green River, WY22 miles from this station, 44.1°F a year
- Bitter Creek (4 mi NE), WY28 miles from this station, 43.7°F a year
- Buckboard Marina, WY37 miles from this station, 43.9°F a year
- Farson, WY42 miles from this station, 37.8°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made