Casper, 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 Casper's primary NOAA station, CASPER 1SW.
The climate verdict for Casper
Dryness leads the climate profile for Casper, Wyoming, with 15.9 inches of precipitation a year. NOAA records an annual average of 47°F. At 52/100 (moderate) the climate comfort score falls in the bottom third of the station-mapped U.S. score corpus, exceeding only 24% of scores.
- 47°F
- yearly average temperature, NOAA normal
- 52/100
- comfort score, above 24% of station-mapped location scores
- 15.9"
- annual precipitation
- 142 days
- frost-free growing season
Casper: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00481572 · Casper, WY 47°F mean · 15.9" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-DRY · SWING-WIDE · COMF-LOW · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 47°F
- RANK-COOL #1,921
- PHOTO-FINISH ≈ Logan Radio Kvnu
- PRCP-DRY 15.9"
- SWING-WIDE 45°F
- COMF-LOW 52/100
- LOAD-HEAT 7,016 HDD
- STN-1 USC00481572
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Logan Radio Kvnu, UT (+ 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.
- Casper (this station) 47°F
- Cold Racine, WI 47°F
- Hot Blackfoot Fire…, ID 47°F
- Near Logan Radio Kvnu, UT 47°F
- Near Jaffrey Silver…, NH 47°F
Casper 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 · Casper
Casper: 26/100 · grade F
Casper publishes 4 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 2 missing weights rescale to 100.
PlainClimate-derived for Casper, not an official NOAA rating. Rankings still use Comfort Score 52/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 15.9 in · 19.1 from 35 in | 32/100 · F |
| Annual temperature balance | 47.1°F · 20.4° from 67.5°F | 28/100 · F |
| Normal heat + freeze calendar | 186 calendar days | 22/100 · F |
| Frost-free season | 142 days/year | 20/100 · F |
Casper · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Casper is a continental Köppen climate: Dfa
Coldest-month mean 26.9°F and warmest-month mean 72.3°F place this station in continental, no dry season, hot summer climates (Dfa). Class Dfa is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: continental, specifically continental, no dry season, hot summer.
- Köppen code
- Dfa
- Group
- Continental
- Warmest month
- 72.3°F
- Coldest month
- 26.9°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 Casper sits across the climate record
Three NOAA fields for Casper's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 72%
- Among 6,861 stations, Casper sits in the cooler third of annual means.
- Annual precipitation
- Drier than 80%
- Casper's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- 61st percentile swing
- Typical seasonal amplitude versus 6,861 complete station-years.
How Casper compares across U.S. station-mapped locations
Casper's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
52 24th percentile score exceeds 24% 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%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). Below this entry.
- 50–60: 1,329 station-mapped locations (21%). This entry sits in this band.
- 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
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 37°F (3°C) | 16°F (-9°C) | 27°F (-3°C) | 0.5" | 27.6 | 0.0 |
| February | 39°F (4°C) | 17°F (-8°C) | 28°F (-2°C) | 1.0" | 24.0 | 0.0 |
| March | 50°F (10°C) | 25°F (-4°C) | 37°F (3°C) | 1.6" | 21.9 | 0.0 |
| April | 56°F (13°C) | 31°F (0°C) | 44°F (6°C) | 1.8" | 15.5 | 0.0 |
| May | 65°F (18°C) | 40°F (4°C) | 52°F (11°C) | 2.8" | 4.5 | 0.0 |
| June | 78°F (26°C) | 50°F (10°C) | 64°F (18°C) | 1.5" | 0.0 | 4.7 |
| July | 87°F (31°C) | 57°F (14°C) | 72°F (22°C) | 1.2" | 0.0 | 12.2 |
| August | 86°F (30°C) | 54°F (12°C) | 70°F (21°C) | 1.0" | 0.0 | 10.0 |
| September | 75°F (24°C) | 45°F (7°C) | 60°F (16°C) | 1.2" | 1.0 | 2.3 |
| October | 60°F (16°C) | 34°F (1°C) | 47°F (8°C) | 1.7" | 13.4 | 0.0 |
| November | 48°F (9°C) | 26°F (-3°C) | 37°F (3°C) | 0.9" | 21.4 | 0.0 |
| December | 37°F (3°C) | 17°F (-8°C) | 27°F (-3°C) | 0.8" | 26.9 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 89°F around July 24, short of 90°F on every date, while 186 dates carry a normal low at or below freezing, the coldest 15°F near December 28.
The freezing stretch
The normal low stays at or below 32°F into April 24, then returns to freezing around October 22, covering 186 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.
The widest day
August 30 carries the biggest normal gap between afternoon and dawn, 33°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Casper.
Where Casper Stands Nationally
Freezing is routine here by normals standards — the normal low reaches 32°F or colder on about 186 nights a year, more than most ranked stations.
A drier-than-most normal water year — around 16 inches, below what four out of five ranked stations collect.
Casper earns 2 nationally notable standings (outer quintiles) against 6,860 NOAA 1991–2020 normals stations; only those extremes render.
Monthly Precipitation
Average monthly rainfall
Casper 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 15%, with neither reaching the 35% that would mark a distinct wet season. Casper has no dry season to plan around, though it does carry a wide 45.4°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: May averages 2.8" and January 0.5". The three wettest months together take 39% 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.
Frost Dates & Growing Season
First Fall Freeze
October 1
50% probability date
Last Spring Freeze
May 12
50% probability date
Growing Season
142 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
7,016
Higher = more heating needed
Cooling Degree Days
514
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside WY closest to Casper 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 (47°F here).
- Auburn, MI 47°F · 0.0°F off
- Brigham City, UT 47°F · 0.0°F off
- Durham, NH 47°F · 0.0°F off
- Grampian, PA 47°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (15.9" here), excluding temperature-peer places.
- Bagdad, AZ 15.9" · 0.0" off
- Fort Collins, CO 15.9" · 0.0" off
- New England, ND 15.9" · 0.0" off
- Colorado Springs, CO 15.9" · 0.0" off
Data-derived climate profile
How Casper's climate pattern fits together
heating led · dry · mid swing
Casper's energy balance leans toward cold weather: 7,016 annual heating degree days against 514 for cooling. Its 45.4°F seasonal range still makes the monthly rows more useful than the annual average alone.
Only about 142 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.
July and January mark the typical warm and cold ends of the calendar in Casper's middle-range seasonal profile. The measured spread is 45.4°F. The annual average is 47°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Casper's cold-season load does not imply a wet climate. Annual precipitation is 15.9 inches, which places the station in PlainClimate's dry range. Snowfall is not added to the interpretation because its annual value is missing. The snowfall and rainfall fields should be read separately rather than inferred from temperature.
These labels group NOAA 1991-2020 normals from Casper's primary station, so the winter figures are a thirty-year average and not a floor: a single hard season can run well below them. Treat each band as a descriptive range for Casper, not an official NOAA class or a year-ahead forecast.
Questions about Casper's climate
How much rain does Casper get? ▼
How cold does Casper get in winter? ▼
How much energy does heating and cooling require in Casper? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Casper's primary station: CASPER 1SW (USC00481572). 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 5613150). Match rule for Casper: 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 Casper 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.