Fossil Butte, WY Climate: Temperature & Rain by Month
Pulled from NOAA NCEI 1991–2020 normals →: climate measurements used in PlainClimate's documented score
30-year climate normals (1991-2020) from Fossil Butte's primary NOAA station, FOSSIL BUTTE.
The climate verdict for Fossil Butte
Dryness leads the climate profile for Fossil Butte, Wyoming, with 11.7 inches of precipitation a year. NOAA records an annual average of 38°F. July is the warmest month at 63°F and January the coldest at 16°F.
- 38°F
- average temperature, NOAA 1991-2020 normal
- 11.7"
- yearly precipitation total
Fossil Butte: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00483582 · Fossil Butte, WY 38°F mean · 11.7" precip
TEMP-COLD · RANK-COOL · PHOTO-FINISH · PRCP-ARID · SWING-WIDE · COMF-UNK · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COLD 38°F
- RANK-COOL #206
- PHOTO-FINISH ≈ Mt Mansfield
- PRCP-ARID 11.7"
- SWING-WIDE 46°F
- COMF-UNK Comfort n/a
- LOAD-HEAT 9,718 HDD
- STN-1 USC00483582
- BOOK-FULL 5/6 fields
Nearest mean-temperature peer: Mt Mansfield, VT (+ 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.
- Hot Mullan Pass Vor…, ID 39°F
- Near Kemmerer, WY 39°F
- Near Afton, WY 39°F
- Fossil Butte (this station) 38°F
- Near Mt Mansfield, VT 38°F
Fossil Butte 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 · Fossil Butte
Fossil Butte: 5/100 · grade F
Fossil Butte publishes 3 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 3 missing weights rescale to 100.
PlainClimate-derived for Fossil Butte, not an official NOAA rating. Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 11.7 in · 23.3 from 35 in | 18/100 · F |
| Annual temperature balance | 38.4°F · 29.1° from 67.5°F | 1/100 · F |
| Normal heat + freeze calendar | 251 calendar days | 0/100 · F |
Fossil Butte · 2026-08-04 · NOAA NCEI Climate Normals · method .
Fossil Butte is a continental Köppen climate: Dfb
Coldest-month mean 16.2°F and warmest-month mean 62.6°F place this station in continental, no dry season, warm summer climates (Dfb). Class Dfb is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: continental, specifically continental, no dry season, warm summer.
- Köppen code
- Dfb
- Group
- Continental
- Warmest month
- 62.6°F
- Coldest month
- 16.2°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 Fossil Butte sits across the climate record
Three NOAA fields for Fossil Butte's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 97%
- Among 6,861 stations, Fossil Butte sits in the cooler third of annual means.
- Annual precipitation
- Drier than 90%
- Fossil Butte's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- 66th percentile swing
- Typical seasonal amplitude versus 6,861 complete station-years.
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 28°F (-2°C) | 5°F (-15°C) | 16°F (-9°C) | 0.7" | 30.9 | 0.0 |
| February | 31°F (-1°C) | 6°F (-14°C) | 18°F (-8°C) | 0.8" | 27.7 | 0.0 |
| March | 41°F (5°C) | 16°F (-9°C) | 28°F (-2°C) | 0.9" | 30.4 | 0.0 |
| April | 52°F (11°C) | 23°F (-5°C) | 38°F (3°C) | 1.1" | 27.4 | 0.0 |
| May | 63°F (17°C) | 30°F (-1°C) | 46°F (8°C) | 1.5" | 18.8 | 0.0 |
| June | 74°F (23°C) | 35°F (2°C) | 54°F (12°C) | 1.1" | 8.1 | 0.5 |
| July | 83°F (29°C) | 42°F (5°C) | 63°F (17°C) | 0.6" | 1.3 | 5.3 |
| August | 82°F (28°C) | 41°F (5°C) | 61°F (16°C) | 0.9" | 2.2 | 2.1 |
| September | 72°F (22°C) | 32°F (0°C) | 52°F (11°C) | 1.1" | 15.1 | 0.1 |
| October | 57°F (14°C) | 23°F (-5°C) | 40°F (5°C) | 1.3" | 25.7 | 0.0 |
| November | 40°F (5°C) | 14°F (-10°C) | 27°F (-3°C) | 0.9" | 28.9 | 0.0 |
| December | 29°F (-2°C) | 5°F (-15°C) | 17°F (-8°C) | 0.9" | 30.8 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 85°F around July 24, short of 90°F on every date, while 251 dates carry a normal low at or below freezing, the coldest 4°F near December 24.
The freezing stretch
The normal low stays at or below 32°F into May 24, then returns to freezing around September 17, covering 251 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 22, when 32% of years recorded at least a hundredth of an inch. The driest is July 10 at 17%. Summed across the calendar, that is about 93 wet dates a year.
The widest day
July 9 carries the biggest normal gap between afternoon and dawn, 42°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Fossil Butte.
Where Fossil Butte Stands Nationally
Winters bite deep and often: the normal nightly low dips to freezing or below on around 251 nights a year, placing this among the most frost-prone tenth of ranked stations.
Aridity defines the water calendar: about 12 inches in a normal year lands this among the driest tenth of ranked stations.
Fossil Butte earns 2 nationally notable standings (outer quintiles) against 6,860 NOAA 1991–2020 normals stations; only those extremes render.
Monthly Precipitation
Average monthly rainfall
8.5 days with precipitation
8.3 days with precipitation
7.8 days with precipitation
7.7 days with precipitation
9.9 days with precipitation
7.0 days with precipitation
5.1 days with precipitation
6.8 days with precipitation
6.9 days with precipitation
7.4 days with precipitation
8.2 days with precipitation
9.3 days with precipitation
Fossil Butte spreads its precipitation across the year
Neither half of the year dominates here: June through August take 22% of the annual total and December through February 20%, with neither reaching the 35% that would mark a distinct wet season. Fossil Butte has no dry season to plan around, though it does carry a wide 46.4°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: May averages 1.5" and July 0.6". The three wettest months together take 33% 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.
Fossil Butte is dry, and what does fall arrives gently
Only about 93 days a year record measurable precipitation here, 25% of the calendar, and they carry 11.7" between them. At roughly 0.13 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 10 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.
Frost Dates & Growing Season
First Fall Freeze
N/A
50% probability date
Last Spring Freeze
N/A
50% probability date
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
9,718
Higher = more heating needed
Cooling Degree Days
60
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside WY closest to Fossil Butte 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 (38°F here).
- Baudette, MN 38°F · 0.0°F off
- Floodwood, MN 38°F · 0.0°F off
- Pembina, ND 38°F · 0.0°F off
- Van Buren, ME 38°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (11.7" here), excluding temperature-peer places.
- Newman, CA 11.7" · 0.0" off
- Alturas, CA 11.7" · 0.0" off
- El Rito, NM 11.7" · 0.0" off
- Virginia City, NV 11.7" · 0.0" off
Scarce-water calendar
Where Fossil Butte's limited precipitation lands
heating led · dry · mid swing
Fossil Butte's energy balance leans toward cold weather: 9,718 annual heating degree days against 60 for cooling. Its 46.4°F seasonal range still makes the monthly rows more useful than the annual average alone.
A frost-free growing-season length is not available for Fossil Butte. That missing field is kept separate from the observed temperature and precipitation record rather than filled from a regional estimate.
July and January mark the typical warm and cold ends of the calendar in Fossil Butte's middle-range seasonal profile. The measured spread is 46.4°F. The annual average is 38°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Fossil Butte's cold-season load does not imply a wet climate. Annual precipitation is 11.7 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.
Fossil Butte wettest normal
May
May concentrates the scarce annual total (11.7 inches).
Fossil Butte driest normal
July
July is typically driest; arid stations are defined by when water is absent, not by a four-season grid.
Questions about Fossil Butte's climate
How dry is Fossil Butte? ▼
How cold does Fossil Butte get in winter? ▼
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Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Fossil Butte's primary station: FOSSIL BUTTE (USC00483582). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The conservative exact name-and-state crosswalk finds no Census place match, so PlainClimate treats this as a station-mapped location and does not claim it is a municipality. No exact Gazetteer row for Fossil Butte; facility counts that depend on place identity are therefore an upper bound, not a municipal census.
On this page every temperature, precipitation, and derived score for Fossil Butte 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.