Guernsey, Wyoming climate: Normal weather by month, frost dates and records
Guernsey's normal year runs from 14°F January nights to 89°F July afternoons, with 15.1 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.3°C, January lows of −10°C, July highs of 32°C, 384 mm of precipitation a year.
- NOAA stationGuernsey (2 mi NW)
- Station IDUSC00484131
- Location42.28°N 104.77°W
- Elevation4,480 ft (1,366 m)
- From the center2 miles
- Population1,094
On October 23, the normal high in Guernsey is 60°F and the normal low 31°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Guernsey.
- Jan 40° 14°
- Feb 41° 16°
- Mar 52° 25°
- Apr 59° 32°
- May 69° 43°
- Jun 81° 53°
- Jul 89° 60°
- Aug 88° 58°
- Sep 78° 48°
- Oct 63° 34°
- Nov 50° 23°
- Dec 40° 15°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Guernsey each month?
July is the warmest month, with normal highs of 89°F; January the coldest, with normal lows of 14°F. The most precipitation falls in May (2.85 in), the least in December (0.34 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 40°F | 14°F | 27.1°F | 0.66 | – | <1 | 31 | 9 h 20 min |
| February | 41°F | 16°F | 28.4°F | 0.54 | – | <1 | 26 | 10 h 30 min |
| March | 52°F | 25°F | 38.2°F | 0.95 | – | <1 | 22 | 11 h 50 min |
| April | 59°F | 32°F | 45.6°F | 1.75 | – | <1 | 12 | 13 h 20 min |
| May | 69°F | 43°F | 55.6°F | 2.85 | – | 1 | 3 | 14 h 30 min |
| June | 81°F | 53°F | 67.0°F | 2.08 | – | 8 | <1 | 15 h 10 min |
| July | 89°F | 60°F | 74.2°F | 1.73 | – | 17 | <1 | 15 h |
| August | 88°F | 58°F | 72.5°F | 1.20 | – | 14 | <1 | 14 h |
| September | 78°F | 48°F | 62.8°F | 1.20 | – | 6 | 1 | 12 h 30 min |
| October | 63°F | 34°F | 48.7°F | 1.29 | – | <1 | 12 | 11 h 10 min |
| November | 50°F | 23°F | 36.4°F | 0.51 | – | <1 | 25 | 9 h 50 min |
| December | 40°F | 15°F | 27.7°F | 0.34 | – | <1 | 30 | 9 h 10 min |
| Year (annual) | 62°F | 35°F | 48.7°F | 15.10 | – | 46 | 161 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 5°C | −10°C | −2.7°C | 17 mm |
| February | 5°C | −9°C | −2.0°C | 14 mm |
| March | 11°C | −4°C | 3.4°C | 24 mm |
| April | 15°C | 0°C | 7.6°C | 44 mm |
| May | 20°C | 6°C | 13.1°C | 72 mm |
| June | 27°C | 12°C | 19.4°C | 53 mm |
| July | 32°C | 15°C | 23.4°C | 44 mm |
| August | 31°C | 14°C | 22.5°C | 30 mm |
| September | 26°C | 9°C | 17.1°C | 30 mm |
| October | 17°C | 1°C | 9.3°C | 33 mm |
| November | 10°C | −5°C | 2.4°C | 13 mm |
| December | 5°C | −9°C | −2.4°C | 9 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Old Fort Laramie (12 miles away), gets 28 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00484131; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Guernsey?
Normal highs sit between 65°F and 85°F in May, June and September.
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00484131.
When is the last frost in Guernsey?
In Guernsey, the last spring frost (32°F) comes after May 7 in half of years and after May 21 in one year in ten; the first autumn frost comes before October 6 in half of years and before September 23 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 71 year in 10 after May 21; 9 in 10 after April 24
- First autumn frost, half of years before
- October 61 year in 10 before September 23; 9 in 10 before October 18
NOAA puts the median frost-free season at 152 days, and the season without a hard freeze (28°F) at 171 days.
A hard freeze (28°F) comes after April 28 in half of springs and before October 16 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Guernsey in zone 5a in ZIP code 82214, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Guernsey's NOAA station is in zone 5a: the coldest night of a typical year reaches −16°F (15 complete years).
Frost dates for every NOAA station in Wyoming · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00484131; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Guernsey?
In a normal year in Guernsey, 46 days a year reach 90°F (3 of them 100°F or more) and 161 nights fall to 32°F or colder.
- Days at 90°F or more
- 46a normal year
- Days at 100°F or more
- 3a normal year
- Nights at 32°F or colder
- 161a normal year
- Days that stay below freezing
- 30high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00484131.
How sunny is Guernsey?
Over a year 78% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Guernsey, 4.5 kWh per square metre a day. July is the sunniest month (86%) and February the cloudiest (72%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 75% | 2.1 |
| February | 72% | 2.9 |
| March | 73% | 4.2 |
| April | 72% | 5.2 |
| May | 74% | 6.2 |
| June | 82% | 7.2 |
| July | 86% | 7.1 |
| August | 86% | 6.3 |
| September | 84% | 5.0 |
| October | 77% | 3.4 |
| November | 76% | 2.4 |
| December | 72% | 1.8 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Guernsey need?
A normal year in Guernsey brings 6,645 heating degree days, 24% more than the median U.S. place (5,373), and 725 cooling degree days, 20% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,732 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,177 | 0 |
| February | 1,025 | 0 |
| March | 831 | 0 |
| April | 582 | 0 |
| May | 309 | 18 |
| June | 53 | 111 |
| July | 3 | 288 |
| August | 12 | 244 |
| September | 131 | 63 |
| October | 507 | 2 |
| November | 859 | 0 |
| December | 1,156 | 0 |
| Year (annual) | 6,645 | 725 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00484131. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Guernsey been warmer than normal lately?
2023 averaged 48.8°F, 0.1°F above the 1991-2020 normal of 48.7°F. 1 of the 2 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2022 | 48.6°F | −0.1°F | – |
| 2023 | 48.8°F | +0.1°F | – |
Source: observed years: ACIS, station USC00484131. A year counts only with all twelve months complete.
How does Guernsey's climate compare?
Guernsey is warmer than 66 of the other 70 places with their own NOAA record in Wyoming, and wetter than 45. Across the 7,247 U.S. stations with normals, its annual mean of 48.7°F is warmer than 35%.
In the Köppen classification computed from these normals, Guernsey is BSk: cold semi-arid steppe. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Guernsey share this climate record?
Hartville has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Hartville, WY68 people · 4 mi NE
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do Guernsey's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Guernsey. This page uses Guernsey (2 mi NW); the other differs by site and elevation:
| Station | From the center | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Guernsey Dam #2 USC00484126 | 2 mi NW | 4,355 ft | 48.6°F | 14°F | 89°F | 16.1 | – | May 11 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Guernsey's climate
What is the coldest month in Guernsey?
January, with a normal high of 40°F and a normal low of 14°F. The warmest is July (89°F by day, 60°F at night).
Does it snow in Guernsey?
Yes. NOAA publishes no 1991-2020 snowfall normal for Guernsey's NOAA station; the nearest record that keeps one, Old Fort Laramie (12 miles away), records 28 inches of snow in a normal year.
What is the rainiest month in Guernsey?
May, with 2.85 in of precipitation in a normal year; the driest is December with 0.34 in.
What plant hardiness zone is Guernsey in?
The USDA's 2023 map puts Guernsey in zone 5a in ZIP code 82214, the nearest ZIP area. By the same method at Guernsey's NOAA station, the coldest night of a typical year reaches −16°F (15 years, 1991-2020): zone 5a.
How late can frost come in Guernsey?
In half of years the last 32°F night comes after May 7; in one year in ten it comes after May 21. Waiting until May 21 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Wyoming climateThe statewide normals and every place in the state
- Whalen Dam USBR, WY7 miles from this station, 48.1°F a year
- Old Fort Laramie, WY12 miles from this station, 49.1°F a year
- Wheatland, WY15 miles from this station, 49.0°F a year
- Glendo, WY16 miles from this station, 47.8°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made