ETD Bridge over Green River · Photo: Clayton B. Fraser · Public domainHardly any U.S. towns see harsher January nights than Fontenelle
In July the day’s top temperature is typically 84°. The seasons are far apart: from a winter night to a summer afternoon the average spans 82°. It is a dry place: less rain and snow fall here than on almost every U.S. town. If you like long walks, June and August offer highs of 75–82°.
A year in Fontenelle at a glance
Each month’s typical high and low, and what it brings.
What stands out about Fontenelle’s climate
Compared with towns across the U.S., with Fontenelle’s place in Wyoming beside it.
What a year in Fontenelle feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
A freeze is possible in every month
About 243 nights a year fall to 32° or below, and 53 to 0° or below. Frost and day counts come from NOAA’s station at Fontenelle Dam, WY, 1.2 miles from the town’s center, at about the same height.
The 2023 USDA map puts Fontenelle’s center in zone 4a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −27°. 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 27 inches of snow a winter
Snow, measured at Fontenelle Dam, WY, falls mostly in February. Precipitation (rain plus melted snow) adds up to 7 inches a year; May is the wettest month and December the driest. Rain or snow falls on about 58 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Fontenelle
99% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from September 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 Fontenelle Dam, WY.
Living with Fontenelle’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 4a, and frost can come in any month. The longest frost-free stretch in half of years is about 69 days.
Months with highs of 62–84° and lows of 40° or more: June and August. 2.7 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Fontenelle from natural hazards, avalanches are the largest share (83%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Fontenelle and similar climates
TownRatings has no climate map of the towns around Fontenelle yet.
Climates most like Fontenelle’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 |
|---|---|---|---|---|
| Fontenelle, WY | 2° | 84° | 7" | 27" |
| Alamosa, CO | 3° | 82° | 8" | 30" |
| Sidney, MT | 4° | 85° | 15" | 30" |
| Dickinson, ND | 5° | 83° | 16" | 35" |
| Taos, NM | 11° | 84° | 13" | 28" |
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 Fontenelle averaged 1.6° warmer than the 1900s. The biggest change is in March (+3.8°).
A bigger shift than in 64% 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 Fontenelle compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Fontenelle’s place among Wyoming’s.
Fontenelle weather by month
Highs, lows and precipitation from NOAA’s grid at Fontenelle’s center; snow, wet days and snow on the ground from Fontenelle Dam, WY. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 29° | 2° | 0.3" | 5.4" | 3 | 20 | 7° – 24° |
| February | 32° | 6° | 0.3" | 6.6" | 4 | 20 | 11° – 30° |
| March | 44° | 18° | 0.5" | 3.8" | 5 | 8 | 23° – 37° |
| April | 54° | 24° | 0.7" | 2.2" | 5 | 1 | 32° – 44° |
| May | 64° | 33° | 1.3" | 0.6" | 8 | 0 | 43° – 53° |
| June | 75° | 40° | 0.8" | 0.0" | 5 | 0 | 52° – 63° |
| July | 84° | 46° | 0.5" | 0.0" | 5 | 0 | 56° – 70° |
| August | 82° | 44° | 0.8" | 0.0" | 6 | 0 | 58° – 66° |
| September | 72° | 35° | 0.9" | 0.0" | 6 | 0 | 50° – 57° |
| October | 58° | 25° | 0.6" | 1.3" | 4 | 1 | 33° – 47° |
| November | 42° | 14° | 0.3" | 2.1" | 3 | 5 | 16° – 34° |
| December | 29° | 3° | 0.3" | 4.5" | 4 | 18 | 10° – 25° |
| Year | 55° | 24° | 7.1" | 26.5" | 58 | 74 |
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 30°. September is the most reliable, staying within 7°.
Where Fontenelle’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 Fontenelle’s center.
- Snow: Fontenelle Dam, WY (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Fontenelle Dam, WY, 1.2 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 Fontenelle’s climate
What is the weather like in Fontenelle?
A typical July afternoon reaches 84°, a January night drops to 2°, and about 27 inches of snow falls in a normal winter. Colder January nights than all but 88 U.S. towns; cooler July afternoons than 58% of U.S. towns.
How cold does it get in Fontenelle in winter?
January nights average 2°. About 243 nights a year reach 32° or below and 53 reach 0° or below. In the coldest January of the last 30 years the month averaged 7°.
How much snow does Fontenelle get?
About 27 inches in a normal winter at Fontenelle Dam, WY, most of it in February, with snow on the ground about 74 days a year.
How hot does it get in Fontenelle?
July, with a typical high of 84° and a low of 46°. About 4 days a year reach 90° (Fontenelle Dam, WY).
When is the first and last frost in Fontenelle?
There is no reliable frost-free season: at Fontenelle Dam, WY, every month has nights at 32° or below, about 243 a year. In half of years the longest stretch without a freeze is about 69 days.
What growing zone is Fontenelle in?
Zone 4a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −27°.
What is the best time of year to visit Fontenelle?
By one simple rule (highs of 62–84° and lows of 40° or more), June and August. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Fontenelle getting warmer?
Yes: 1991–2020 averaged 1.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 64% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Fontenelle.
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.