Draper-Steadman House · Photo: Kmw usa · CC BY-SA 3.0Riverton reaches 100° on about 13 days a year, more than 92% of U.S. towns
January mornings start at about 21°. Winter and summer sit 70° apart. By precipitation alone, it ranks drier than 94% of U.S. towns. Keep the boiler serviced for the months from November to April, which average under 50°.
A year in Riverton at a glance
Each month’s typical high and low, and what it brings.
What stands out about Riverton’s climate
Compared with towns across the U.S., with Riverton’s place in Utah beside it.
What a year in Riverton feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 174 frost-free days a year
In half of years the last 32° night comes by April 29 and the first by October 22. Day counts come from NOAA’s station at Draper-point Of Mtn, UT, 4 miles from the town’s center, at about the same height; frost dates and degree days from Cottonwood Weir, UT, 12 miles away.
The 2023 USDA map puts Riverton’s center in zone 7a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 4°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 82 inches of snow a winter
Snow, measured at Cottonwood Weir, UT, falls mostly in December. Precipitation (rain plus melted snow) adds up to 14 inches a year; May is the wettest month and July the driest. Rain or snow falls on about 89 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Riverton
82% of the work is heating. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Cottonwood Weir, UT.
Living with Riverton’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
174 frost-free days in zone 7a. The last frost comes by Apr 29 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 22.
Months with highs of 62–84° and lows of 40° or more: May, June and September. 13 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Riverton from natural hazards, earthquakes are the largest share (56%); heat waves, cold waves, winter storms and ice storms together are 4%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Riverton and its neighbors
Every town next door is within a degree of Riverton in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Riverton’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Riverton, UT | 21° | 91° | 14" | 82" |
| Thornton, CO | 18° | 90° | 14" | 74" |
| Casper, WY | 15° | 89° | 12" | 82" |
| Pocatello, ID | 19° | 87° | 15" | 64" |
| Chadron, NE | 14° | 89° | 18" | 50" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Riverton averaged 1.6° warmer than the 1900s. The biggest change is in March (+3.0°).
A bigger shift than in 68% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Riverton compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Riverton’s place among Utah’s.
Riverton weather by month
Highs, lows and precipitation from NOAA’s grid at Riverton’s center; snow, wet days and snow on the ground from Cottonwood Weir, UT. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 38° | 21° | 1.1" | 17.0" | 9 | 24° – 37° |
| February | 44° | 24° | 1.3" | 18.4" | 8 | 29° – 41° |
| March | 53° | 32° | 1.4" | 7.6" | 9 | 37° – 49° |
| April | 60° | 37° | 1.7" | 5.6" | 10 | 44° – 55° |
| May | 71° | 46° | 1.7" | 0.3" | 9 | 52° – 63° |
| June | 82° | 54° | 0.8" | 0.0" | 5 | 62° – 74° |
| July | 91° | 62° | 0.6" | 0.0" | 3 | 68° – 80° |
| August | 89° | 60° | 0.8" | 0.0" | 5 | 71° – 79° |
| September | 79° | 50° | 1.2" | 0.0" | 6 | 61° – 69° |
| October | 64° | 39° | 1.4" | 1.5" | 8 | 44° – 57° |
| November | 50° | 29° | 1.2" | 8.2" | 8 | 31° – 47° |
| December | 39° | 21° | 1.2" | 23.3" | 9 | 26° – 35° |
| Year | 63° | 40° | 14.3" | 81.9" | 89 |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 31° to 47°. August is the most reliable, staying within 8°.
Where Riverton’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Riverton’s center.
- Snow: Cottonwood Weir, UT.
- Frost dates, heating and cooling: Cottonwood Weir, UT, 12 miles away.
- Freezing nights, 90° and 100° days: Draper-point Of Mtn, UT, 4 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Riverton’s climate
What is the weather like in Riverton?
A typical July afternoon reaches 91°, a January night drops to 21°, and about 82 inches of snow falls in a normal winter. Colder January nights than 54% of U.S. towns; hotter July afternoons than 84% of U.S. towns.
How cold does it get in Riverton in winter?
January nights average 21°. About 116 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 24°.
How much snow does Riverton get?
About 82 inches in a normal winter at Cottonwood Weir, UT, most of it in December.
How hot does it get in Riverton?
July, with a typical high of 91° and a low of 62°. About 78 days a year reach 90° and 13 reach 100° (Cottonwood Weir, UT).
When is the first and last frost in Riverton?
In half of years the last spring frost (32°) comes by April 29 and the first fall frost by October 22, about 174 frost-free days, at Cottonwood Weir, UT.
What growing zone is Riverton in?
Zone 7a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 4°.
What is the best time of year to visit Riverton?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Riverton getting warmer?
Yes: 1991–2020 averaged 1.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 68% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Riverton.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.