Frost Dates for Troy, MT

Elevation: 588 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 14
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 25

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 21
First Fall Frost September 18

Hard Freeze (28°F)

Last Spring Hard Freeze April 29
First Fall Hard Freeze October 6
48.48°N, 115.91°W © OpenStreetMap

Growing Season

134 Days May 14 to September 25

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 6b

Avg. annual minimum: −5 to 0°F

Learn more

Köppen Climate

The Köppen climate classification system categorizes climates based on temperature and precipitation patterns.
Dsb Warm-Summer Continental (Dry Summer)

Warm, dry summers and cold, snowy winters. Common in mountain regions. Moderate growing season with irrigation needs in summer.

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
January33°28°23°
February39°31°24°
March50°39°28°
April59°46°33°
May70°55°40°
June76°61°46°
July87°68°49°
August86°67°48°
September75°58°42°
October57°46°35°
November41°35°29°
December32°28°24°

Precipitation

Precipitation table
Average monthly precipitation (inches)
MonthPrecipitation
January3.8
February3.0
March3.6
April3.1
May3.1
June2.8
July2.5
August2.8
September3.3
October3.8
November4.2
December4.2

Sunrise / Sunset

Daylight Longest: 15h 55m · Shortest: 8h 05m
Sunrise and sunset table
Sunrise, sunset, and daylight on the 15th of each month (local solar time)
Month Sunrise Sunset Daylight
January7:44 AM4:16 PM8h 31m
February7:02 AM4:58 PM9h 56m
March6:13 AM5:47 PM11h 34m
April5:17 AM6:43 PM13h 26m
May4:30 AM7:30 PM15h 01m
June4:03 AM7:57 PM15h 53m
July4:14 AM7:46 PM15h 32m
August4:56 AM7:04 PM14h 09m
September5:50 AM6:10 PM12h 20m
October6:44 AM5:16 PM10h 32m
November7:32 AM4:28 PM8h 55m
December7:57 AM4:03 PM8h 07m

Nearby Stations

Libby, MTMay 10 - September 26 Libby 1 Ne Rs, MT May 23 - September 21 Bonners Ferry, ID April 30 - October 4 Libby Dam (Base), MT May 11 - October 1 Heron 2 Nw, MT May 20 - September 20 Cabinet Gorge, ID May 9 - October 8

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