Photo: Idawriter · CC BY-SA 3.0Precipitation in Guernsey trails that of 94% of U.S. towns: 14 inches a year
Deep winter brings January lows near 14°. Temperatures cover 76° across the year, low to high. By January nights alone, it runs colder than 88% of U.S. towns. Homes need heating from October to April, the months averaging under 50°.
A year in Guernsey at a glance
Each month’s typical high and low, and what it brings.
What stands out about Guernsey’s climate
Compared with towns across the U.S., with Guernsey’s place in Wyoming beside it.
What a year in Guernsey feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 152 frost-free days a year
In half of years the last 32° night comes by May 7 and the first by October 6. Frost and day counts come from NOAA’s station at Guernsey 2nw, WY, 1.7 miles from the town’s center, 140 ft higher.
The 2023 USDA map puts Guernsey’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −19°. 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 28 inches of snow a winter
Snow, measured at Old Ft Laramie, WY, falls mostly in February and December. Precipitation (rain plus melted snow) adds up to 14 inches a year; May is the wettest month and January the driest. Rain or snow falls on about 70 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Guernsey
90% 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 Guernsey 2nw, WY.
Living with Guernsey’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
152 frost-free days in zone 5a. The last frost comes by May 7 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 6.
Months with highs of 62–84° and lows of 40° or more: June and September.
Parks & trails →Of the yearly building losses FEMA expects in Guernsey from natural hazards, river flooding is the largest share (42%); heat waves, cold waves, winter storms and ice storms together are 21%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Guernsey and similar climates
TownRatings has no climate map of the towns around Guernsey yet.
Climates most like Guernsey’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 |
|---|---|---|---|---|
| Guernsey, WY | 14° | 89° | 14" | 28" |
| Ephraim, UT | 14° | 89° | 12" | 20" |
| Cortez, CO | 15° | 91° | 12" | 33" |
| Lockwood, MT | 15° | 88° | 15" | 35" |
| 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 Guernsey averaged 1.7° warmer than the 1900s. The biggest change is in March (+3.6°).
A bigger shift than in 69% 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 Guernsey compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Guernsey’s place among Wyoming’s.
Guernsey weather by month
Highs, lows and precipitation from NOAA’s grid at Guernsey’s center; snow, wet days and snow on the ground from Old Ft Laramie, WY. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 41° | 14° | 0.3" | 2.2" | 4 | 5 | 22° – 35° |
| February | 43° | 15° | 0.4" | 6.3" | 5 | 5 | 18° – 37° |
| March | 54° | 23° | 0.8" | 3.1" | 5 | 3 | 28° – 47° |
| April | 61° | 30° | 1.8" | 3.5" | 7 | 2 | 39° – 51° |
| May | 70° | 40° | 2.5" | 0.6" | 10 | 0 | 48° – 60° |
| June | 82° | 49° | 2.1" | 0.0" | 8 | 0 | 60° – 71° |
| July | 89° | 56° | 1.5" | 0.0" | 7 | 0 | 67° – 77° |
| August | 88° | 53° | 1.2" | 0.0" | 6 | 0 | 66° – 75° |
| September | 79° | 43° | 1.1" | 0.0" | 6 | 0 | 56° – 66° |
| October | 64° | 31° | 1.1" | 2.4" | 6 | 1 | 39° – 53° |
| November | 50° | 21° | 0.4" | 3.2" | 4 | 3 | 24° – 44° |
| December | 41° | 13° | 0.4" | 6.2" | 4 | 6 | 19° – 32° |
| Year | 63° | 32° | 13.5" | 27.5" | 70 | 25 |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 24° to 44°. August is the most reliable, staying within 9°.
Where Guernsey’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 Guernsey’s center.
- Snow: Old Ft Laramie, WY.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Guernsey 2nw, WY, 1.7 miles from the town’s center, 140 ft higher; 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 Guernsey’s climate
What is the weather like in Guernsey?
A typical July afternoon reaches 89°, a January night drops to 14°, and about 28 inches of snow falls in a normal winter. Colder January nights than 88% of U.S. towns; hotter July afternoons than 74% of U.S. towns.
How cold does it get in Guernsey in winter?
December nights average 13°. About 161 nights a year reach 32° or below and 11 reach 0° or below. In the coldest December of the last 30 years the month averaged 19°.
How much snow does Guernsey get?
About 28 inches in a normal winter at Old Ft Laramie, WY, most of it in February and December, with snow on the ground about 25 days a year.
How hot does it get in Guernsey?
July, with a typical high of 89° and a low of 56°. About 46 days a year reach 90° and 3 reach 100° (Guernsey 2nw, WY).
When is the first and last frost in Guernsey?
In half of years the last spring frost (32°) comes by May 7 and the first fall frost by October 6, about 152 frost-free days, at Guernsey 2nw, WY.
What growing zone is Guernsey in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −19°.
What is the best time of year to visit Guernsey?
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 Guernsey getting warmer?
Yes: 1991–2020 averaged 1.7° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 69% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Guernsey.
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.