Frost Dates for Gibson Dam, MT

Elevation: 1399 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. June 12
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. September 8

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 June 20
First Fall Frost September 2

Hard Freeze (28°F)

Last Spring Hard Freeze May 19
First Fall Hard Freeze September 24
47.60°N, 112.75°W © OpenStreetMap

Growing Season

88 Days June 12 to September 8

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 4b

Avg. annual minimum: −25 to −20°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
January36°24°12°
February36°24°12°
March43°31°19°
April50°38°25°
May59°46°33°
June67°53°39°
July79°62°45°
August78°60°43°
September68°52°36°
October54°41°29°
November42°31°20°
December35°24°13°

Precipitation

Precipitation table
Average monthly precipitation (inches)
MonthPrecipitation
January2.9
February2.4
March2.7
April3.4
May4.4
June4.5
July3.4
August4.0
September3.9
October3.9
November3.5
December3.4

Sunrise / Sunset

Daylight Longest: 15h 47m · Shortest: 8h 13m
Sunrise and sunset table
Sunrise, sunset, and daylight on the 15th of each month (local solar time)
Month Sunrise Sunset Daylight
January7:41 AM4:19 PM8h 38m
February6:60 AM5:00 PM10h 00m
March6:12 AM5:48 PM11h 35m
April5:18 AM6:42 PM13h 24m
May4:32 AM7:28 PM14h 55m
June4:07 AM7:53 PM15h 45m
July4:18 AM7:42 PM15h 25m
August4:58 AM7:02 PM14h 05m
September5:50 AM6:10 PM12h 19m
October6:43 AM5:17 PM10h 35m
November7:29 AM4:31 PM9h 01m
December7:53 AM4:07 PM8h 14m

Nearby Stations

Augusta, MTMay 19 - September 21 Choteau, MTMay 28 - September 12 Bynum 4 Sse, MT May 16 - September 27 Blackleaf, MTJune 9 - September 3 Rogers Pass 9 Nne, MT May 21 - September 15 Fairfield, MT May 13 - September 27

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