Riverton, Wyoming climate: Normal weather by month, frost dates and records
Riverton's normal year runs from 8°F January nights to 88°F July afternoons, with 8.6 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.9°C, January lows of −13°C, July highs of 31°C, 217 mm of precipitation a year.
- NOAA stationRiverton
- Station IDUSW00024061
- Location43.07°N 108.48°W
- Elevation5,568 ft (1,697 m)
- Population10,953
On October 22, the normal high in Riverton is 55°F and the normal low 29°F, and the chance of measurable rain or snow is 15%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Riverton.
- Jan 31° 8°
- Feb 36° 12°
- Mar 49° 23°
- Apr 57° 30°
- May 67° 40°
- Jun 79° 48°
- Jul 88° 56°
- Aug 86° 54°
- Sep 74° 44°
- Oct 58° 32°
- Nov 43° 19°
- Dec 31° 8°
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 Riverton each month?
July is the warmest month, with normal highs of 88°F; January the coldest, with normal lows of 8°F. The most precipitation falls in May (1.92 in), the least in December (0.26 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 31°F | 8°F | 19.2°F | 0.29 | 3 | <1 | 31 | 9 h 20 min |
| February | 36°F | 12°F | 23.7°F | 0.40 | 5 | <1 | 28 | 10 h 30 min |
| March | 49°F | 23°F | 35.6°F | 0.65 | 5 | <1 | 27 | 11 h 50 min |
| April | 57°F | 30°F | 43.5°F | 1.20 | 8 | <1 | 17 | 13 h 20 min |
| May | 67°F | 40°F | 53.2°F | 1.92 | 9 | <1 | 4 | 14 h 40 min |
| June | 79°F | 48°F | 63.4°F | 0.94 | 6 | 4 | <1 | 15 h 20 min |
| July | 88°F | 56°F | 71.9°F | 0.54 | 4 | 15 | <1 | 15 h |
| August | 86°F | 54°F | 69.6°F | 0.42 | 5 | 10 | <1 | 14 h |
| September | 74°F | 44°F | 59.2°F | 0.77 | 5 | 1 | 2 | 12 h 30 min |
| October | 58°F | 32°F | 44.7°F | 0.83 | 6 | <1 | 15 | 11 h 10 min |
| November | 43°F | 19°F | 30.8°F | 0.34 | 4 | <1 | 28 | 9 h 50 min |
| December | 31°F | 8°F | 19.6°F | 0.26 | 4 | <1 | 31 | 9 h |
| Year (annual) | 58°F | 31°F | 44.5°F | 8.56 | 63 | 31 | 182 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −1°C | −13°C | −7.1°C | 7 mm |
| February | 2°C | −11°C | −4.6°C | 10 mm |
| March | 9°C | −5°C | 2.0°C | 17 mm |
| April | 14°C | −1°C | 6.4°C | 30 mm |
| May | 19°C | 4°C | 11.8°C | 49 mm |
| June | 26°C | 9°C | 17.4°C | 24 mm |
| July | 31°C | 13°C | 22.2°C | 14 mm |
| August | 30°C | 12°C | 20.9°C | 11 mm |
| September | 23°C | 7°C | 15.1°C | 20 mm |
| October | 14°C | 0°C | 7.1°C | 21 mm |
| November | 6°C | −7°C | −0.7°C | 9 mm |
| December | −1°C | −13°C | −6.9°C | 7 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. Riverton's own co-op station Riverton station does: 44 inches of snow in a normal year (see the other stations below).
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024061; 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 Riverton?
Normal highs sit between 65°F and 85°F in May, June and September. Of those, September has the fewest days with rain (5).
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 USW00024061.
When is the last frost in Riverton?
In Riverton, the last spring frost (32°F) comes after May 16 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 15 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 161 year in 10 after May 31; 9 in 10 after May 1
- First autumn frost, half of years before
- September 281 year in 10 before September 15; 9 in 10 before October 12
NOAA puts the median frost-free season at 133 days, and the season without a hard freeze (28°F) at 154 days.
A hard freeze (28°F) comes after May 3 in half of springs and before October 7 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Riverton in zone 5a in ZIP code 82501, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Riverton's NOAA station is in zone 5a: the coldest night of a typical year reaches −17°F (24 complete years).
Frost dates for every NOAA station in Wyoming · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00024061; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. 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 Riverton?
In a normal year in Riverton, 31 days a year reach 90°F (1 of them 100°F or more), 182 nights fall to 32°F or colder and 63 days bring measurable precipitation.
- Days at 90°F or more
- 31a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 182a normal year
- Days that stay below freezing
- 56high of 32°F or less
- Days with 0.01 inch of precipitation
- 63a normal year
The highest temperature in this station's record (since 1996) is 104°F, on July 12, 2026; the lowest is −31°F, on January 31, 2023.
The wettest calendar year on that record is 2017, with 14.97 in; the snowiest season is 2022–23, with 87.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00024061; records: ACIS (NOAA Regional Climate Centers), station USW00024061. Records use complete months only; a month missing more than three days is left out.
How sunny is Riverton?
Over a year 80% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Riverton, 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 much heating and cooling does Riverton need?
A normal year in Riverton brings 7,927 heating degree days, 48% more than the median U.S. place (5,373), and 499 cooling degree days, 45% 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 2,248 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,418 | 0 |
| February | 1,156 | 0 |
| March | 912 | 0 |
| April | 647 | 0 |
| May | 375 | 8 |
| June | 115 | 67 |
| July | 10 | 224 |
| August | 26 | 169 |
| September | 205 | 31 |
| October | 628 | 1 |
| November | 1,028 | 0 |
| December | 1,407 | 0 |
| Year (annual) | 7,927 | 499 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024061. 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 Riverton been warmer than normal lately?
2025 averaged 47.2°F, 2.7°F above the 1991-2020 normal of 44.5°F. 3 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 46.9°F | +2.4°F | 8.85 |
| 2022 | 44.3°F | −0.2°F | 9.56 |
| 2023 | 41.6°F | −2.9°F | 14.13 |
| 2024 | 46.9°F | +2.4°F | 6.27 |
| 2025 | 47.2°F | +2.7°F | 9.14 |
Source: observed years: ACIS, station USW00024061. A year counts only with all twelve months complete.
How does Riverton's climate compare?
Riverton is warmer than 35 of the other 70 places with their own NOAA record in Wyoming, and wetter than 13. Across the 7,247 U.S. stations with normals, its annual mean of 44.5°F is warmer than 17%.
In the Köppen classification computed from these normals, Riverton is BSk: cold semi-arid steppe. 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 Riverton share this climate record?
Arapahoe 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.
- Arapahoe, WY1,460 people · 5 mi S
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do Riverton's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Riverton. This page uses Riverton; the other differs by site and elevation:
| Station | From this station | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Riverton station USC00487760 | 6 mi SE | 4,955 ft | 44.0°F | 4°F | 88°F | 9.5 | 44 | May 12 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Riverton's climate
What is the coldest month in Riverton?
January, with a normal high of 31°F and a normal low of 8°F. The warmest is July (88°F by day, 56°F at night).
Does it snow in Riverton?
Yes. NOAA publishes no 1991-2020 snowfall normal for Riverton's NOAA station; Riverton's own co-op station Riverton station records 44 inches of snow in a normal year.
What is the rainiest month in Riverton?
May, with 1.92 in of precipitation in a normal year; the driest is December with 0.26 in.
What plant hardiness zone is Riverton in?
The USDA's 2023 map puts Riverton in zone 5a in ZIP code 82501, the nearest ZIP area. By the same method at Riverton's NOAA station, the coldest night of a typical year reaches −17°F (24 years, 1991-2020): zone 5a.
How late can frost come in Riverton?
In half of years the last 32°F night comes after May 16; 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
- Pavillion, WY17 miles from this station, 45.0°F a year
- Lander, WY21 miles from this station, 45.1°F a year
- Shoshoni, WY22 miles from this station, 45.6°F a year
- Diversion Dam, WY25 miles from this station, 43.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made