Thermopolis (21 mi WNW), Wyoming climate: Climate normals at a NOAA weather station
Thermopolis (21 mi WNW)'s normal year runs from 10°F December nights to 86°F July afternoons. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.0°C, December lows of −12°C, July highs of 30°C.
- NOAA stationThermopolis (21 mi WNW)
- Station IDUSC00488888
- Location43.72°N 108.70°W
- Elevation5,510 ft (1,679 m)
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Thermopolis (21 mi WNW).
- Jan 39° 10°
- Feb 41° 12°
- Mar 50° 20°
- Apr 57° 28°
- May 66° 37°
- Jun 78° 44°
- Jul 86° 51°
- Aug 85° 50°
- Sep 75° 41°
- Oct 60° 29°
- Nov 47° 18°
- Dec 39° 10°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Thermopolis (21 mi WNW) each month?
July is the warmest month, with normal highs of 86°F; December the coldest, with normal lows of 10°F.
| Month | High | Low | Mean | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|
| January | 39°F | 10°F | 24.7°F | – | <1 | 31 | 9 h 20 min |
| February | 41°F | 12°F | 26.3°F | – | <1 | 28 | 10 h 30 min |
| March | 50°F | 20°F | 35.1°F | – | <1 | 28 | 11 h 50 min |
| April | 57°F | 28°F | 42.2°F | – | <1 | 23 | 13 h 20 min |
| May | 66°F | 37°F | 51.4°F | – | <1 | 10 | 14 h 40 min |
| June | 78°F | 44°F | 60.9°F | – | 2 | 2 | 15 h 30 min |
| July | 86°F | 51°F | 68.3°F | – | 8 | <1 | 15 h 10 min |
| August | 85°F | 50°F | 67.2°F | – | 5 | 1 | 14 h |
| September | 75°F | 41°F | 58.0°F | – | 1 | 5 | 12 h 30 min |
| October | 60°F | 29°F | 44.6°F | – | <1 | 21 | 11 h 10 min |
| November | 47°F | 18°F | 32.4°F | – | <1 | 29 | 9 h 40 min |
| December | 39°F | 10°F | 24.1°F | – | <1 | 31 | 9 h |
| Year (annual) | 60°F | 29°F | 44.6°F | – | 15 | 207 |
The same normals in °C and millimetres
| Month | High | Low | Mean |
|---|---|---|---|
| January | 4°C | −12°C | −4.1°C |
| February | 5°C | −11°C | −3.2°C |
| March | 10°C | −6°C | 1.7°C |
| April | 14°C | −2°C | 5.7°C |
| May | 19°C | 3°C | 10.8°C |
| June | 25°C | 7°C | 16.1°C |
| July | 30°C | 10°C | 20.2°C |
| August | 29°C | 10°C | 19.6°C |
| September | 24°C | 5°C | 14.4°C |
| October | 16°C | −2°C | 7.0°C |
| November | 8°C | −8°C | 0.2°C |
| December | 4°C | −12°C | −4.4°C |
NOAA publishes no 1991-2020 snowfall normal for this station, and no record within 25 miles keeps one, so snow is left out here rather than estimated.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00488888; 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.
Which months are mildest at Thermopolis (21 mi WNW)?
Normal highs sit between 65°F and 85°F in May, June, August and September.
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 USC00488888.
When is the last frost at Thermopolis (21 mi WNW)?
In Thermopolis (21 mi WNW), the last spring frost (32°F) comes after May 29 in half of years and after June 19 in one year in ten; the first autumn frost comes before September 17 in half of years and before September 3 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 291 year in 10 after June 19; 9 in 10 after May 14
- First autumn frost, half of years before
- September 171 year in 10 before September 3; 9 in 10 before October 1
NOAA puts the median frost-free season at 110 days, and the season without a hard freeze (28°F) at 134 days.
A hard freeze (28°F) comes after May 14 in half of springs and before September 29 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Thermopolis (21 mi WNW) in zone 5a in ZIP code 82443, 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 USC00488888; 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 at Thermopolis (21 mi WNW)?
In a normal year in Thermopolis (21 mi WNW), 15 days a year reach 90°F and 207 nights fall to 32°F or colder.
- Days at 90°F or more
- 15a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 207a normal year
- Days that stay below freezing
- 30high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00488888.
How sunny is it at Thermopolis (21 mi WNW)?
Over a year 80% of the sunlight that would reach the ground under clear skies gets through the clouds at Thermopolis (21 mi WNW), 4.6 kWh per square metre a day. July is the sunniest month (87%) and December the cloudiest (71%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 77% | 2.1 |
| February | 77% | 3.1 |
| March | 76% | 4.3 |
| April | 75% | 5.5 |
| May | 76% | 6.4 |
| June | 84% | 7.5 |
| July | 87% | 7.3 |
| August | 86% | 6.4 |
| September | 85% | 5.1 |
| October | 78% | 3.4 |
| November | 76% | 2.3 |
| December | 71% | 1.7 |
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 many heating and cooling degree days does Thermopolis (21 mi WNW) record?
A normal year at Thermopolis (21 mi WNW) brings 7,724 heating degree days, 44% more than the median U.S. place (5,373), and 322 cooling degree days, 64% 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 1,903 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,251 | 0 |
| February | 1,082 | 0 |
| March | 926 | 0 |
| April | 684 | 0 |
| May | 425 | 3 |
| June | 159 | 37 |
| July | 41 | 143 |
| August | 45 | 113 |
| September | 234 | 25 |
| October | 634 | 0 |
| November | 976 | 0 |
| December | 1,268 | 0 |
| Year (annual) | 7,724 | 322 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00488888. 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.
How does Thermopolis (21 mi WNW)'s climate compare?
Thermopolis (21 mi WNW) is warmer than 36 of the 71 places with their own NOAA record in Wyoming. Across the 7,247 U.S. stations with normals, its annual mean of 44.6°F is warmer than 18%.
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers.
Which places near Thermopolis (21 mi WNW) share this climate record?
Owl Creek 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.
- Owl Creek, WY0 people · 8 mi NE
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 Thermopolis (21 mi WNW)'s climate
What is the coldest month at Thermopolis (21 mi WNW)?
December, with a normal high of 39°F and a normal low of 10°F. The warmest is July (86°F by day, 51°F at night).
What plant hardiness zone is Thermopolis (21 mi WNW) in?
The USDA's 2023 map puts Thermopolis (21 mi WNW) in zone 5a in ZIP code 82443, the nearest ZIP area.
How late can frost come at Thermopolis (21 mi WNW)?
In half of years the last 32°F night comes after May 29; in one year in ten it comes after June 19. Waiting until June 19 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Wyoming climateThe statewide normals and every place in the state
- Thermopolis, WY25 miles from this station, 48.6°F a year
- Sunshine (3 mi NE), WY27 miles from this station, 38.7°F a year
- Pavillion, WY33 miles from this station, 45.0°F a year
- Boysen Dam, WY35 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