Frost Dates for Guernsey 2nw, WY

Elevation: 1366 m

Frost Dates

Last Spring Frost (50%) A 50% chance that the last spring frost has already passed by this date. Most gardeners use this as their primary planting guide. May 7
First Fall Frost (50%) A 50% chance that the first fall frost has occurred by this date. Plan to harvest or protect tender plants before this date. October 6

30% Probability

Only a 30% chance of frost remaining by this date. Use these dates for a safer planting window, especially for tender plants sensitive to cold.
Last Spring Frost May 13
First Fall Frost October 1

Hard Freeze (28°F)

Last Spring Hard Freeze April 28
First Fall Hard Freeze October 16
42.28°N, 104.77°W © OpenStreetMap

Growing Season

152 Days May 7 to October 6

USDA Hardiness Zone

Hardiness zones indicate which perennial plants can survive winter in your area. For annual vegetables, frost dates and growing season length matter more than hardiness zone.
Zone 5b

Avg. annual minimum: −15 to −10°F

Learn more

Köppen Climate

The Köppen climate classification system categorizes climates based on temperature and precipitation patterns.
BSk Cold Semi-Arid (Steppe)

Cool to cold with low rainfall and wide temperature swings. Common in the western Great Plains and central Asia. Short growing seasons benefit from season extension techniques.

Köppen climate map

Temperature

Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)
Temperature table
Average monthly temperatures (°F)
Month Avg High Avg Temp Avg Low
January40°27°14°
February41°28°16°
March52°38°25°
April59°46°32°
May69°56°43°
June81°67°53°
July89°74°60°
August88°73°58°
September78°63°48°
October63°49°34°
November50°36°23°
December40°28°15°

Precipitation

Precipitation table
Average monthly precipitation (inches)
MonthPrecipitation
January1.6
February1.6
March2.3
April3.7
May4.8
June4.4
July4.2
August4.3
September4.2
October3.6
November2.5
December1.8

Sunrise / Sunset

Daylight Mountain Time (MT) Longest: 15h 06m · Shortest: 8h 54m
Sunrise and sunset table
Sunrise, sunset, and daylight on the 15th of each month (Mountain Time (MT))
Month Sunrise Sunset Daylight
January7:31 AM4:45 PM9h 14m
February7:03 AM5:24 PM10h 21m
March7:19 AM6:58 PM11h 39m
April6:25 AM7:34 PM13h 09m
May5:43 AM8:07 PM14h 24m
June5:27 AM8:32 PM15h 05m
July5:41 AM8:29 PM14h 48m
August6:12 AM7:55 PM13h 43m
September6:46 AM7:02 PM12h 16m
October7:20 AM6:09 PM10h 49m
November6:58 AM4:31 PM9h 33m
December7:27 AM4:22 PM8h 55m

Nearby Stations

Guernsey Dam #2, WY May 11 - October 3 Whalen Dam Usbr, WY May 7 - October 3 Old Ft Laramie, WY May 14 - September 26 Wheatland 4 N, WY May 19 - September 22 Glendo Rsvr Usbr, WY May 9 - October 5 Glendo 6ne, WY May 25 - September 15

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