Big Horn, Wyoming climate: Normal weather by month, frost dates and records
Big Horn's normal year runs from 14°F December nights to 84°F July afternoons, with 18.6 inches of precipitation and 81 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.5°C, December lows of −10°C, July highs of 29°C, 472 mm of precipitation a year.
- NOAA stationBig Horn
- Station IDUSC00480680
- Location44.68°N 107.01°W
- Elevation4,208 ft (1,283 m)
- Population (census place)7
On October 23, the normal high in Big Horn is 56°F and the normal low 30°F, and the chance of measurable rain or snow is 29%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Big Horn.
- Jan 38° 15°
- Feb 38° 15°
- Mar 48° 23°
- Apr 55° 31°
- May 64° 40°
- Jun 74° 48°
- Jul 84° 54°
- Aug 84° 53°
- Sep 74° 45°
- Oct 59° 33°
- Nov 46° 22°
- Dec 38° 14°
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 Big Horn each month?
July is the warmest month, with normal highs of 84°F; December the coldest, with normal lows of 14°F. The most precipitation falls in May (3.79 in), the least in December (0.58 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 38°F | 15°F | 26.3°F | 0.60 | 11.4 | 7 | <1 | 30 | 9 h 10 min |
| February | 38°F | 15°F | 26.3°F | 0.62 | 16.1 | 9 | <1 | 27 | 10 h 20 min |
| March | 48°F | 23°F | 35.3°F | 1.77 | 13.6 | 8 | <1 | 25 | 11 h 50 min |
| April | 55°F | 31°F | 42.8°F | 2.42 | 10.2 | 11 | <1 | 18 | 13 h 30 min |
| May | 64°F | 40°F | 51.9°F | 3.79 | 2.0 | 15 | <1 | 5 | 14 h 50 min |
| June | 74°F | 48°F | 61.1°F | 2.30 | 0.0 | 10 | 2 | <1 | 15 h 30 min |
| July | 84°F | 54°F | 69.2°F | 0.95 | 0.0 | 7 | 10 | <1 | 15 h 20 min |
| August | 84°F | 53°F | 68.4°F | 1.06 | 0.0 | 7 | 8 | <1 | 14 h 10 min |
| September | 74°F | 45°F | 59.0°F | 1.70 | 1.0 | 7 | 2 | 1 | 12 h 40 min |
| October | 59°F | 33°F | 45.6°F | 1.95 | 6.2 | 10 | <1 | 15 | 11 h |
| November | 46°F | 22°F | 34.4°F | 0.85 | 9.2 | 7 | <1 | 26 | 9 h 40 min |
| December | 38°F | 14°F | 25.7°F | 0.58 | 11.7 | 6 | <1 | 30 | 8 h 50 min |
| Year (annual) | 58°F | 33°F | 45.5°F | 18.59 | 81.4 | 106 | 23 | 177 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 3°C | −9°C | −3.2°C | 15 mm | 29 cm |
| February | 3°C | −10°C | −3.2°C | 16 mm | 41 cm |
| March | 9°C | −5°C | 1.8°C | 45 mm | 35 cm |
| April | 13°C | 0°C | 6.0°C | 61 mm | 26 cm |
| May | 18°C | 5°C | 11.1°C | 96 mm | 5 cm |
| June | 23°C | 9°C | 16.2°C | 58 mm | 0 cm |
| July | 29°C | 12°C | 20.7°C | 24 mm | 0 cm |
| August | 29°C | 12°C | 20.2°C | 27 mm | 0 cm |
| September | 23°C | 7°C | 15.0°C | 43 mm | 3 cm |
| October | 15°C | 0°C | 7.6°C | 50 mm | 16 cm |
| November | 8°C | −5°C | 1.3°C | 22 mm | 23 cm |
| December | 3°C | −10°C | −3.5°C | 15 mm | 30 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00480680; 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 Big Horn?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, August has the fewest days with rain (7).
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 USC00480680.
When is the last frost in Big Horn?
In Big Horn, the last spring frost (32°F) comes after May 17 in half of years and after May 31 in one year in ten; the first autumn frost comes before September 28 in half of years and before September 13 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 171 year in 10 after May 31; 9 in 10 after May 2
- First autumn frost, half of years before
- September 281 year in 10 before September 13; 9 in 10 before October 10
NOAA puts the median frost-free season at 132 days, and the season without a hard freeze (28°F) at 155 days.
A hard freeze (28°F) comes after May 2 in half of springs and before October 5 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Big Horn in zone 5a in ZIP code 82842, the nearest ZIP area.
Frost dates for every NOAA station in Wyoming · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00480680; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. 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 Big Horn?
In a normal year in Big Horn, 23 days a year reach 90°F (1 of them 100°F or more), 177 nights fall to 32°F or colder and 106 days bring measurable precipitation.
- Days at 90°F or more
- 23a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 177a normal year
- Days that stay below freezing
- 41high of 32°F or less
- Days with 0.01 inch of precipitation
- 106a normal year
- Days with 1 inch of snow or more
- 23a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00480680.
How sunny is Big Horn?
Over a year 77% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Big Horn, 4.4 kWh per square metre a day. July is the sunniest month (87%) and April the cloudiest (69%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 75% | 2.0 |
| February | 76% | 3.0 |
| March | 73% | 4.0 |
| April | 69% | 5.0 |
| May | 70% | 5.9 |
| June | 81% | 7.2 |
| July | 87% | 7.3 |
| August | 86% | 6.2 |
| September | 83% | 4.9 |
| October | 74% | 3.1 |
| November | 72% | 2.0 |
| December | 70% | 1.6 |
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 Big Horn need?
A normal year in Big Horn brings 7,471 heating degree days, 39% more than the median U.S. place (5,373), and 398 cooling degree days, 56% 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 2,082 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,200 | 0 |
| February | 1,085 | 0 |
| March | 921 | 0 |
| April | 666 | 0 |
| May | 412 | 6 |
| June | 154 | 39 |
| July | 29 | 158 |
| August | 45 | 150 |
| September | 222 | 42 |
| October | 602 | 3 |
| November | 918 | 0 |
| December | 1,218 | 0 |
| Year (annual) | 7,471 | 398 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00480680. 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 Big Horn been warmer than normal lately?
2025 averaged 46.9°F, 1.4°F above the 1991-2020 normal of 45.5°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 46.2°F | +0.7°F | 14.60 | 95.6 |
| 2022 | 45.2°F | −0.3°F | 15.97 | 94.5 |
| 2023 | 45.8°F | +0.3°F | 24.77 | 104.8 |
| 2024 | 47.6°F | +2.1°F | 11.38 | 54.4 |
| 2025 | 46.9°F | +1.4°F | 22.29 | 92.0 |
Source: observed years: ACIS, station USC00480680. A year counts only with all twelve months complete.
How does Big Horn's climate compare?
Big Horn is warmer than 48 of the other 70 places with their own NOAA record in Wyoming, and wetter than 57. Across the 7,247 U.S. stations with normals, its annual mean of 45.5°F is warmer than 21%.
In the Köppen classification computed from these normals, Big Horn is Dfb: continental, no dry season, warm summer. 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 Big Horn share this climate record?
Powder Horn has no NOAA station with 1991-2020 normals of its 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.
- Powder Horn, WY818 people · 2 mi E
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Big Horn's climate
What is the coldest month in Big Horn?
December, with a normal high of 38°F and a normal low of 14°F. The warmest is July (84°F by day, 54°F at night).
Does it snow in Big Horn?
Yes: 81 inches in a normal year, falling on 42 days with 0.1 inch or more, the most in February (16.1 inches).
What is the rainiest month in Big Horn?
May, with 3.79 in of precipitation in a normal year; the driest is December with 0.58 in.
What plant hardiness zone is Big Horn in?
The USDA's 2023 map puts Big Horn in zone 5a in ZIP code 82842, the nearest ZIP area.
How late can frost come in Big Horn?
In half of years the last 32°F night comes after May 17; in one year in ten it comes after May 31. Waiting until May 31 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Wyoming climateThe statewide normals and every place in the state
- Sheridan, WY6 miles from this station, 45.4°F a year
- Story, WY9 miles from this station, 43.5°F a year
- Dayton, WY18 miles from this station, 43.9°F a year
- Buffalo, WY25 miles from this station, 46.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made