Rock Springs, WY Climate: Temperature & Rain by Month
Annual temperature and rainfall from NOAA NCEI's 1991–2020 normals →; comfort score computed by PlainClimate
30-year climate normals (1991-2020) from Rock Springs's primary NOAA station, ROCK SPRINGS AP.
The climate verdict for Rock Springs
Dryness leads the climate profile for Rock Springs, Wyoming, with 7.5 inches of precipitation a year. NOAA records an annual average of 44°F. At 24/100 (below average) the climate comfort score falls in the bottom third of the station-mapped U.S. score corpus, exceeding only 0% of scores.
- 44°F
- annual average temperature (NOAA normal)
- 24/100
- comfort score, above 0% of station-mapped location scores
- 7.5"
- annual precipitation · 54" snow
- 129 days
- growing season, frost-free days
Rock Springs: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USW00024027 · Rock Springs, WY 44°F mean · 7.5" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-ARID · SWING-WIDE · COMF-LOW · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 44°F
- RANK-COOL #961
- PHOTO-FINISH ≈ Lowville
- PRCP-ARID 7.5"
- SWING-WIDE 48°F
- COMF-LOW 24/100
- LOAD-HEAT 8,064 HDD
- STN-1 USW00024027
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Lowville, NY (+ 0 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every WY station list.
- Rock Springs (this station) 44°F
- Cold Clearmont, WY 44°F
- Hot Powder Rvr, WY 44°F
- Near Lowville, NY 44°F
- Near Lake City, MI 44°F
Rock Springs sits in Wyoming, the #5 coldest U.S. state at 43.3°F statewide annual average - see all 50 coldest states ranked by NOAA normals
Climate Living Index · Rock Springs
Rock Springs: 14/100 · grade F
Rock Springs publishes all six Living Index dimensions from NOAA annual/seasonal normals · NOAA daily multivariate normals · NOAA hourly normals.
PlainClimate-derived for Rock Springs, not an official NOAA rating. Rankings still use Comfort Score 24/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Normal heat + freeze calendar | 191 calendar days | 19/100 · F |
| Snowfall burden | 54.0 inches/year | 19/100 · F |
| Annual temperature balance | 43.7°F · 23.8° from 67.5°F | 15/100 · F |
| Summer moisture balance | 34.5°F mean dew point | 12/100 · F |
| Frost-free season | 129 days/year | 11/100 · F |
| Precipitation balance | 7.5 in · 27.4 from 35 in | 6/100 · F |
Rock Springs · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Rock Springs's normals sit in a dry climate class: BSk
Precipitation is low relative to temperature but above true desert thresholds: cold semi-arid steppe (BSk). Class BSk is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: dry (arid or semi-arid), specifically cold semi-arid steppe.
- Köppen code
- BSk
- Group
- Dry (arid or semi-arid)
- Warmest month
- 69.4°F
- Coldest month
- 21.4°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · heating-led station
Where Rock Springs sits across the climate record
Three NOAA fields for Rock Springs's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 86%
- Among 6,861 stations, Rock Springs sits in the cooler third of annual means.
- Annual precipitation
- Drier than 97%
- Rock Springs's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- Wider than 73%
- Warmest-to-coldest month gap for Rock Springs is large versus 6,861 complete station-years.
How Rock Springs compares across U.S. station-mapped locations
Rock Springs's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
24 0th percentile score exceeds 0% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). This entry sits in this band.
- 30–40: 280 station-mapped locations (5%). Above this entry.
- 40–50: 1,113 station-mapped locations (18%). Above this entry.
- 50–60: 1,329 station-mapped locations (21%). Above this entry.
- 60–70: 1,236 station-mapped locations (20%). Above this entry.
- 70–80: 650 station-mapped locations (11%). Above this entry.
- 80–90: 921 station-mapped locations (15%). Above this entry.
- 90–100: 564 station-mapped locations (9%). Above this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Rock Springs's measured station temperature trend
MethodologyAcross 85 complete annual observations from 1911 to 2025, ROCK SPRINGS AP warmed at a fitted rate of 0.22°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Rock Springs primary station fitted change +0.22 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 30°F (-1°C) | 14°F (-10°C) | 22°F (-6°C) | 0.4" | 8.2" | 30.8 | 0.0 |
| February | 33°F (0°C) | 16°F (-9°C) | 24°F (-4°C) | 0.4" | 7.9" | 27.4 | 0.0 |
| March | 44°F (7°C) | 24°F (-4°C) | 34°F (1°C) | 0.6" | 6.4" | 27.5 | 0.0 |
| April | 53°F (12°C) | 30°F (-1°C) | 41°F (5°C) | 0.9" | 8.8" | 20.7 | 0.0 |
| May | 63°F (17°C) | 38°F (4°C) | 51°F (10°C) | 1.3" | 2.7" | 7.2 | 0.0 |
| June | 75°F (24°C) | 47°F (8°C) | 61°F (16°C) | 0.7" | 0.4" | 0.7 | 1.1 |
| July | 84°F (29°C) | 55°F (13°C) | 69°F (21°C) | 0.5" | 0.0" | 0.0 | 6.6 |
| August | 82°F (28°C) | 53°F (12°C) | 67°F (20°C) | 0.6" | 0.0" | 0.0 | 2.1 |
| September | 71°F (22°C) | 44°F (7°C) | 57°F (14°C) | 0.8" | 1.2" | 2.1 | 0.1 |
| October | 56°F (13°C) | 33°F (0°C) | 45°F (7°C) | 0.8" | 6.6" | 15.0 | 0.0 |
| November | 41°F (5°C) | 22°F (-6°C) | 31°F (0°C) | 0.4" | 6.0" | 26.7 | 0.0 |
| December | 30°F (-1°C) | 13°F (-10°C) | 21°F (-6°C) | 0.3" | 5.8" | 30.6 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 85°F around July 22, short of 90°F on every date, while 191 dates carry a normal low at or below freezing, the coldest 13°F near December 19.
The freezing stretch
The normal low stays at or below 32°F into April 26, then returns to freezing around October 19, covering 191 dates in all.
Derived from the normal daily minimum. This is a different measure from the 50%-probability frost dates shown elsewhere on this page, which come from NOAA’s frost product.
Where the wet dates fall
The likeliest wet date is May 7, when 29% of years recorded at least a hundredth of an inch. The driest is July 6 at 15%. Summed across the calendar, that is about 72 wet dates a year.
The widest day
July 5 carries the biggest normal gap between afternoon and dawn, 30°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Rock Springs.
Where Rock Springs Stands Nationally
Aridity defines the water calendar: about 8 inches in a normal year lands this among the driest tenth of ranked stations.
Freezing is routine here by normals standards — the normal low reaches 32°F or colder on about 191 nights a year, more than most ranked stations.
Rock Springs earns 2 nationally notable standings (outer quintiles) against 6,860 NOAA 1991–2020 normals stations; only those extremes render.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 8.2"
5.3 days with precipitation
Snow: 7.9"
5.1 days with precipitation
Snow: 6.4"
6.6 days with precipitation
Snow: 8.8"
8.3 days with precipitation
Snow: 2.7"
9.0 days with precipitation
Snow: 0.4"
5.5 days with precipitation
4.7 days with precipitation
6.0 days with precipitation
Snow: 1.2"
6.1 days with precipitation
Snow: 6.6"
5.9 days with precipitation
Snow: 6.0"
4.8 days with precipitation
Snow: 5.8"
4.8 days with precipitation
Rock Springs spreads its precipitation across the year
Neither half of the year dominates here: June through August take 23% of the annual total and December through February 14%, with neither reaching the 35% that would mark a distinct wet season. Rock Springs has no dry season to plan around, though it does carry a wide 48°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: May averages 1.3" and December 0.3". The three wettest months together take 40% of the year, against the 25% a perfectly flat distribution would give them.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. "Spread across the year" means neither the June-August nor the December-February share reaches 35%; it describes an average year, not the variability of any single one.
Rock Springs is dry, and what does fall arrives gently
Only about 72 days a year record measurable precipitation here, 20% of the calendar, and they carry 7.5" between them. At roughly 0.10 inches on an average wet day, this is not the damp drizzle of a marine climate; it is an arid record in which precipitation is both uncommon and light when it appears.
The wettest month by count is May at about 9 wet days; the driest is July at about 5.
A low per-event average in a dry record is a statement about typical days only. Arid regions can still take a large share of a year's total from a single convective storm, which a normal cannot show.
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, not the extremes within it.
Winter brings real snow to Rock Springs
Rock Springs averages 54.0 inches of snowfall a year, with April the snowiest month on the normals, spread across roughly 42 days that record measurable snow. That is depth accumulating on the ground, which is why it can exceed the annual precipitation figure: precipitation counts the liquid the snow melts down to, and fresh snow is mostly air.
- Annual snowfall: 54.0 inches of depth.
- Days recording measurable snow: about 42 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 72% of the year's precipitation.
NOAA 1991-2020 normals. The ten-to-one ratio is a convention, not a measurement: real ratios vary with temperature, so treat the share as an order of magnitude rather than an exact split.
Frost Dates & Growing Season
First Fall Freeze
September 28
50% probability date
Last Spring Freeze
May 22
50% probability date
Growing Season
129 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
8,064
Higher = more heating needed
Cooling Degree Days
319
Higher = more cooling needed
Warmest Month
July
Coldest Month
December
Humidity & Wind
Monthly averages from hourly observations
| Month | Humidity | Wind (mph) | Clear Sky % | Overcast % |
|---|---|---|---|---|
| January | 67% | 12.4 | 54% | 20% |
| February | 62% | 12.3 | 53% | 18% |
| March | 51% | 12.6 | 48% | 19% |
| April | 45% | 12.5 | 46% | 18% |
| May | 42% | 11.0 | 53% | 12% |
| June | 30% | 10.0 | 69% | 3% |
| July | 33% | 8.8 | 65% | 5% |
| August | 33% | 9.1 | 65% | 5% |
| September | 42% | 10.0 | 68% | 11% |
| October | 52% | 11.5 | 59% | 19% |
| November | 63% | 11.8 | 57% | 20% |
| December | 67% | 11.9 | 56% | 21% |
Nationwide similar cities
Other rankable U.S. places outside WY closest to Rock Springs on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (44°F here).
- Beach, ND 44°F · 0.0°F off
- Benson, MN 44°F · 0.0°F off
- Cheboygan, MI 44°F · 0.0°F off
- Conrad, MT 44°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (7.5" here), excluding temperature-peer places.
- Delano, CA 7.5" · 0.0" off
- Kettleman City, CA 7.5" · 0.0" off
- Quincy, WA 7.5" · 0.1" off
- Sunnyside, WA 7.7" · 0.1" off
Snow and freeze rhythm
When cold and snow define Rock Springs
heating led · dry · mid swing
Rock Springs's energy balance leans toward cold weather: 8,064 annual heating degree days against 319 for cooling. Its 48.0°F seasonal range still makes the monthly rows more useful than the annual average alone.
Only about 129 days are frost-free in a normal year. That short interval is consistent with the cold-season signal, but the measure does not predict the exact first or last freeze in any one year.
-
1. Rock Springs coldest normal
December
Averaging 21°F (-6°C), this month sits below freezing for the month as a whole, not merely overnight.
-
2. Rock Springs typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Rock Springs snow peak
April
Rock Springs averages 54.0 inches of snow a year, with April the snowiest month on the normals.
Questions about Rock Springs's climate
How much snow does Rock Springs get? ▼
How cold does Rock Springs get in winter? ▼
How much energy does heating and cooling require in Rock Springs? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Rock Springs's primary station: ROCK SPRINGS AP (USW00024027). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The 2024 Census Gazetteer identifies the exact name-and-state match as an incorporated place (GEOID 5667235). Match rule for Rock Springs: exact normalized name + state only, no fuzzy expansion, so nearby differently spelled facilities stay unmatched.
On this page every temperature, precipitation, and derived score for Rock Springs comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.