Photo: Magicpiano · CC BY-SA 4.0Green River’s winters are colder and snowier than most of the U.S.
A typical July afternoon reaches 87°, a January night drops to 9°, and about 39 inches of snow falls in a normal winter.
A year in Green River at a glance
Each month’s typical high and low, and what it brings.
What stands out about Green River’s climate
Compared with towns across the U.S., with Green River’s place in Wyoming beside it.
What a year in Green River feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 120 frost-free days a year
In half of years the last 32° night comes by May 24 and the first by September 22. Frost and day counts come from NOAA’s station at Green Rvr, WY, 0.2 miles from the town’s center, 120 ft lower.
The 2023 USDA map puts Green River’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −18°. 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 39 inches of snow a winter
Snow, measured at Green Rvr, WY, falls mostly in February. Precipitation (rain plus melted snow) adds up to 9 inches a year; May is the wettest month and November the driest. Rain or snow falls on about 71 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Green River
96% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Green Rvr, WY.
Living with Green River’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
120 frost-free days in zone 5a. The last frost comes by May 24 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 22.
Months with highs of 62–84° and lows of 40° or more: June and September. 55 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Green River from natural hazards, river flooding is the largest share (55%); heat waves, cold waves, winter storms and ice storms together are 33%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Green River and similar climates
TownRatings has no climate map of the towns around Green River yet.
Climates most like Green River’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 |
|---|---|---|---|---|
| Green River, WY | 9° | 87° | 9" | 39" |
| Salida, CO | 10° | 85° | 8" | 37" |
| Havre, MT | 6° | 85° | 13" | 41" |
| Taos, NM | 11° | 84° | 13" | 28" |
| Spring Creek, NV | 15° | 89° | 14" | 41" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Green River averaged 1.2° warmer than the 1900s. The biggest change is in March (+3.2°).
A smaller shift than in 63% 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 Green River compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Green River’s place among Wyoming’s.
Green River weather by month
Highs, lows and precipitation from NOAA’s grid at Green River’s center; snow, wet days and snow on the ground from Green Rvr, WY. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 32° | 9° | 0.4" | 6.3" | 5 | 19 | 12° – 29° |
| February | 36° | 12° | 0.5" | 7.6" | 5 | 17 | 11° – 32° |
| March | 47° | 22° | 0.7" | 5.4" | 6 | 7 | 25° – 39° |
| April | 56° | 28° | 1.0" | 3.9" | 7 | 2 | 37° – 48° |
| May | 66° | 37° | 1.4" | 0.9" | 9 | 0 | 45° – 57° |
| June | 78° | 45° | 0.9" | 0.0" | 5 | 0 | 55° – 67° |
| July | 87° | 52° | 0.5" | 0.0" | 5 | 0 | 61° – 74° |
| August | 85° | 50° | 0.8" | 0.0" | 5 | 0 | 64° – 71° |
| September | 75° | 40° | 1.0" | 0.3" | 6 | 0 | 53° – 61° |
| October | 60° | 30° | 0.9" | 2.4" | 6 | 1 | 37° – 52° |
| November | 43° | 19° | 0.4" | 5.0" | 5 | 7 | 21° – 39° |
| December | 32° | 10° | 0.5" | 6.7" | 6 | 19 | 15° – 29° |
| Year | 58° | 29° | 8.9" | 38.5" | 71 | 72 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 11° to 32°. August is the most reliable, staying within 8°.
Where Green River’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 Green River’s center.
- Snow: Green Rvr, WY (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Green Rvr, WY, 0.2 miles from the town’s center, 120 ft lower; 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 Green River’s climate
What is the weather like in Green River?
A typical July afternoon reaches 87°, a January night drops to 9°, and about 39 inches of snow falls in a normal winter. Colder January nights than 95% of U.S. towns; hotter July afternoons than 63% of U.S. towns.
How cold does it get in Green River in winter?
January nights average 9°. About 200 nights a year reach 32° or below and 24 reach 0° or below. In the coldest January of the last 30 years the month averaged 12°.
How much snow does Green River get?
About 39 inches in a normal winter at Green Rvr, WY, most of it in February, with snow on the ground about 72 days a year.
How hot does it get in Green River?
July, with a typical high of 87° and a low of 52°. About 30 days a year reach 90° (Green Rvr, WY).
When is the first and last frost in Green River?
In half of years the last spring frost (32°) comes by May 24 and the first fall frost by September 22, about 120 frost-free days, at Green Rvr, WY.
What growing zone is Green River in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −18°.
What is the best time of year to visit Green River?
By one simple rule (highs of 62–84° and lows of 40° or more), June and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Green River getting warmer?
Yes: 1991–2020 averaged 1.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 63% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Green River.
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.