Frost Dates for Hebgen Dam, MT
Elevation: 1978 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 15
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 10
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 23
First Fall Frost
September 3
Hard Freeze (28°F)
Last Spring Hard Freeze
May 24
First Fall Hard Freeze
September 26
Growing Season
87 Days
June 15 to September 10
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 3b
Avg. annual minimum: −35 to −30°F
Köppen Climate
The Köppen climate classification system categorizes climates based on temperature and precipitation patterns.
Dfc
Subarctic
Short, cool summers and long, very cold winters. Growing seasons of 3–4 months require fast-maturing varieties. Root vegetables, potatoes, and cold-hardy greens are the most reliable.
Temperature
0°
20°
40°
60°
80°
Avg High
Avg Temp
Avg Low
Light Frost (32°F)
Hard Frost (28°F)
Temperature table
| Month | Avg High | Avg Temp | Avg Low |
|---|---|---|---|
| January | 23° | 13° | 4° |
| February | 28° | 17° | 5° |
| March | 38° | 26° | 14° |
| April | 47° | 35° | 23° |
| May | 58° | 45° | 32° |
| June | 68° | 54° | 39° |
| July | 79° | 62° | 45° |
| August | 78° | 61° | 43° |
| September | 68° | 53° | 37° |
| October | 51° | 39° | 28° |
| November | 34° | 26° | 18° |
| December | 23° | 14° | 6° |
Precipitation
0"
2"
4"
5.5"
Precipitation table
| Month | Precipitation |
|---|---|
| January | 4.8 |
| February | 4.5 |
| March | 5.0 |
| April | 5.1 |
| May | 5.5 |
| June | 4.6 |
| July | 3.6 |
| August | 3.8 |
| September | 4.5 |
| October | 4.9 |
| November | 5.0 |
| December | 4.9 |
Sunrise / Sunset
Daylight
Longest: 15h 25m · Shortest: 8h 35m
Sunrise and sunset table
| Month | Sunrise | Sunset | Daylight |
|---|---|---|---|
| January | 7:31 AM | 4:29 PM | 8h 58m |
| February | 6:54 AM | 5:06 PM | 10h 11m |
| March | 6:11 AM | 5:49 PM | 11h 38m |
| April | 5:22 AM | 6:38 PM | 13h 16m |
| May | 4:41 AM | 7:19 PM | 14h 38m |
| June | 4:18 AM | 7:42 PM | 15h 23m |
| July | 4:28 AM | 7:32 PM | 15h 05m |
| August | 5:03 AM | 6:57 PM | 13h 53m |
| September | 5:51 AM | 6:09 PM | 12h 18m |
| October | 6:39 AM | 5:21 PM | 10h 42m |
| November | 7:21 AM | 4:39 PM | 9h 18m |
| December | 7:42 AM | 4:18 PM | 8h 37m |
Nearby Stations
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