Frost Dates for Grantsburg, WI

Elevation: 302 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 11
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 1

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 18
First Fall Frost September 25

Hard Freeze (28°F)

Last Spring Hard Freeze April 30
First Fall Hard Freeze October 11
45.77°N, 92.69°W © OpenStreetMap

Growing Season

143 Days May 11 to October 1

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 4a

Avg. annual minimum: −30 to −25°F

Learn more

Köppen Climate

The Köppen climate classification system categorizes climates based on temperature and precipitation patterns.
Dfb Warm-Summer Continental

Warm summers and cold, snowy winters. A shorter growing season than hot-summer continental. Hardy vegetables, root crops, and cool-season greens do well. Season extension is valuable.

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
January22°12°1°
February28°17°5°
March41°29°18°
April56°43°31°
May69°56°44°
June78°66°53°
July82°70°58°
August80°68°56°
September72°60°47°
October58°46°35°
November41°32°22°
December27°18°10°

Precipitation

Precipitation table
Average monthly precipitation (inches)
MonthPrecipitation
January1.9
February2.3
March4.0
April4.4
May4.8
June5.1
July5.2
August5.7
September4.1
October3.7
November3.1
December2.5

Sunrise / Sunset

Daylight Central Time (CT) Longest: 15h 32m · Shortest: 8h 28m
Sunrise and sunset table
Sunrise, sunset, and daylight on the 15th of each month (Central Time (CT))
Month Sunrise Sunset Daylight
January7:54 AM4:46 PM8h 51m
February7:21 AM5:29 PM10h 08m
March7:32 AM7:09 PM11h 37m
April6:32 AM7:50 PM13h 18m
May5:45 AM8:29 PM14h 44m
June5:26 AM8:56 PM15h 30m
July5:41 AM8:52 PM15h 11m
August6:17 AM8:13 PM13h 57m
September6:56 AM7:14 PM12h 18m
October7:36 AM6:16 PM10h 40m
November7:19 AM4:32 PM9h 13m
December7:52 AM4:21 PM8h 30m

Nearby Stations

Luck, WIMay 6 - October 4 Wild Rvr Sp, MN May 19 - September 25 Hinckley, MNMay 16 - September 24 Danbury, WIMay 11 - September 30 St Croix Falls, WI May 4 - October 8 Sandstone 6 W, MN May 13 - September 29

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