Riverton, 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 Riverton's primary NOAA station, RIVERTON - 2 stations mapped to the area.
The climate verdict for Riverton
Dryness leads the climate profile for Riverton, Wyoming, with 8.6 inches of precipitation a year. NOAA records an annual average of 45°F. At 28/100 (below average) the climate comfort score falls in the bottom third of the station-mapped U.S. score corpus, exceeding only 0% of scores.
- 45°F
- annual average temperature (NOAA normal)
- 28/100
- comfort score, above 0% of station-mapped location scores
- 8.6"
- annual precipitation
- 135 days
- frost-free days per growing season
Riverton: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USW00024061 · Riverton, WY 45°F mean · 8.6" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-ARID · SWING-WIDE · COMF-LOW · LOAD-HEAT · STN-MULTI · BOOK-FULL
- TEMP-COOL 45°F
- RANK-COOL #1,166
- PHOTO-FINISH ≈ Moorcroft
- PRCP-ARID 8.6"
- SWING-WIDE 53°F
- COMF-LOW 28/100
- LOAD-HEAT 7,927 HDD
- STN-MULTI USW00024061
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Moorcroft, WY (+ 0.1 °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.
- Riverton (this station) 45°F
- Hot Worland, WY 45°F
- Near Moorcroft, WY 45°F
- Near Estherville, IA 45°F
- Near Sparta, WI 45°F
Riverton 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 · Riverton
Riverton: 16/100 · grade F
Riverton publishes 4 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 2 missing weights rescale to 100.
PlainClimate-derived for Riverton, not an official NOAA rating. Rankings still use Comfort Score 28/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Annual temperature balance | 44.5°F · 23.0° from 67.5°F | 18/100 · F |
| Normal heat + freeze calendar | 193 calendar days | 18/100 · F |
| Frost-free season | 135 days/year | 15/100 · F |
| Precipitation balance | 8.6 in · 26.4 from 35 in | 8/100 · F |
Riverton · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Riverton's normals sit in a dry climate class: BSk
Precipitation is low relative to temperature but above true desert thresholds: cold semi-arid steppe (BSk). Class BSk is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: dry (arid or semi-arid), specifically cold semi-arid steppe.
- Köppen code
- BSk
- Group
- Dry (arid or semi-arid)
- Warmest month
- 71.9°F
- Coldest month
- 19.2°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 Riverton sits across the climate record
Three NOAA fields for Riverton's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 83%
- Among 6,861 stations, Riverton sits in the cooler third of annual means.
- Annual precipitation
- Drier than 96%
- Riverton's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- Wider than 88%
- Warmest-to-coldest month gap for Riverton is large versus 6,861 complete station-years.
How Riverton compares across U.S. station-mapped locations
Riverton's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
28 0th percentile score exceeds 0% 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%). This entry sits in this band.
- 30–40: 280 station-mapped locations (5%). Above this entry.
- 40–50: 1,113 station-mapped locations (18%). Above this entry.
- 50–60: 1,329 station-mapped locations (21%). Above this entry.
- 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 | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 31°F (-1°C) | 8°F (-13°C) | 19°F (-7°C) | 0.3" | N/A | 30.8 | 0.0 |
| February | 36°F (2°C) | 12°F (-11°C) | 24°F (-5°C) | 0.4" | N/A | 27.5 | 0.0 |
| March | 49°F (9°C) | 23°F (-5°C) | 36°F (2°C) | 0.7" | N/A | 26.8 | 0.0 |
| April | 57°F (14°C) | 30°F (-1°C) | 44°F (6°C) | 1.2" | N/A | 17.1 | 0.0 |
| May | 67°F (19°C) | 40°F (4°C) | 53°F (12°C) | 1.9" | N/A | 4.4 | 0.1 |
| June | 79°F (26°C) | 48°F (9°C) | 63°F (17°C) | 0.9" | N/A | 0.1 | 4.4 |
| July | 88°F (31°C) | 56°F (13°C) | 72°F (22°C) | 0.5" | N/A | 0.0 | 15.4 |
| August | 86°F (30°C) | 54°F (12°C) | 70°F (21°C) | 0.4" | N/A | 0.0 | 9.8 |
| September | 74°F (23°C) | 44°F (7°C) | 59°F (15°C) | 0.8" | N/A | 1.5 | 1.3 |
| October | 58°F (14°C) | 32°F (0°C) | 45°F (7°C) | 0.8" | N/A | 14.8 | 0.0 |
| November | 43°F (6°C) | 19°F (-7°C) | 31°F (-1°C) | 0.3" | N/A | 27.7 | 0.0 |
| December | 31°F (-1°C) | 8°F (-13°C) | 20°F (-7°C) | 0.3" | N/A | 30.8 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 89°F around July 22, short of 90°F on every date, while 193 dates carry a normal low at or below freezing, the coldest 7°F near December 25.
The freezing stretch
The normal low stays at or below 32°F into April 24, then returns to freezing around October 15, covering 193 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 9, when 29% of years recorded at least a hundredth of an inch. The driest is January 11 at 12%. Summed across the calendar, that is about 63 wet dates a year.
The widest day
July 5 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 Riverton.
Where Riverton Stands Nationally
Aridity defines the water calendar: about 9 inches in a normal year lands this among the driest tenth of ranked stations.
Freezing is routine here by normals standards — the normal low reaches 32°F or colder on about 193 nights a year, more than most ranked stations.
Riverton earns 2 nationally notable standings (outer quintiles) against 6,860 NOAA 1991–2020 normals stations; only those extremes render.
Monthly Precipitation
Average monthly rainfall and snowfall
3.2 days with precipitation
5.1 days with precipitation
4.5 days with precipitation
7.7 days with precipitation
8.8 days with precipitation
5.9 days with precipitation
3.8 days with precipitation
4.8 days with precipitation
5.1 days with precipitation
5.7 days with precipitation
3.8 days with precipitation
4.3 days with precipitation
Riverton 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 11%, with neither reaching the 35% that would mark a distinct wet season. Riverton has no dry season to plan around, though it does carry a wide 52.7°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: May averages 1.9" and December 0.3". The three wettest months together take 47% 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.
Riverton is dry, and what does fall arrives gently
Only about 63 days a year record measurable precipitation here, 17% of the calendar, and they carry 8.6" between them. At roughly 0.14 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 9 wet days; the driest is January at about 3.
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
September 28
50% probability date
Last Spring Freeze
May 16
50% probability date
Growing Season
135 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
7,927
Higher = more heating needed
Cooling Degree Days
499
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside WY closest to Riverton 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 (45°F here).
- Amidon, ND 45°F · 0.0°F off
- Cadillac, MI 45°F · 0.0°F off
- Canton, NY 45°F · 0.0°F off
- Cavendish, VT 45°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (8.6" here), excluding temperature-peer places.
- Boardman, OR 8.6" · 0.0" off
- Socorro, NM 8.6" · 0.0" off
- Yakima, WA 8.6" · 0.0" off
- Hanford, CA 8.5" · 0.0" off
Scarce-water calendar
Where Riverton's limited precipitation lands
heating led · dry · mid swing
Riverton's energy balance leans toward cold weather: 7,927 annual heating degree days against 499 for cooling. Its 52.7°F seasonal range still makes the monthly rows more useful than the annual average alone.
Only about 135 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 Riverton's middle-range seasonal profile. The measured spread is 52.7°F. The annual average is 45°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Riverton's cold-season load does not imply a wet climate. Annual precipitation is 8.6 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.
Riverton wettest normal
May
May concentrates the scarce annual total (8.6 inches).
Riverton driest normal
December
December is typically driest; arid stations are defined by when water is absent, not by a four-season grid.
Questions about Riverton's climate
How dry is Riverton? ▼
How many days above 90°F does Riverton get? ▼
How much energy does heating and cooling require in Riverton? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Riverton's primary station: RIVERTON (USW00024061). 2 NOAA stations are mapped to the Riverton area; the primary station's record is used for consistency. 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 5666220). Match rule for Riverton: 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 Riverton 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.