Frost Dates for Sun Prairie, MT

Based on data from Great Falls Intl AP weather station, 6 miles away

Frost Dates

Last Spring Frost (50%) iA 50% chance that the last spring frost has already passed by this date. Most gardeners use this as their primary planting guide. May 19
First Fall Frost (50%) iA 50% chance that the first fall frost has occurred by this date. Plan to harvest or protect tender plants before this date. September 24
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

30% Probability iOnly 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 25
First Fall Frost September 19

Hard Freeze (28°F)

Last Spring Hard Freeze May 5
First Fall Hard Freeze October 3
47.54°N, -111.48°W © OpenStreetMap

Growing Season

128 Days May 19 to September 24

USDA Hardiness Zone iHardiness 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 (−32 to −29°C)

Learn more

Köppen Climate iThe 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

10° 30° 50° 70° 90°
25°
High: 35°F
Avg: 25°F
Low: 15°F
Jan
26°
High: 37°F
Avg: 26°F
Low: 15°F
Feb
34°
High: 46°F
Avg: 34°F
Low: 22°F
Mar
42°
High: 55°F
Avg: 42°F
Low: 30°F
Apr
52°
High: 65°F
Avg: 52°F
Low: 38°F
May
59°
High: 73°F
Avg: 59°F
Low: 46°F
Jun
68°
High: 84°F
Avg: 68°F
Low: 51°F
Jul
67°
High: 83°F
Avg: 67°F
Low: 50°F
Aug
57°
High: 72°F
Avg: 57°F
Low: 43°F
Sep
45°
High: 57°F
Avg: 45°F
Low: 33°F
Oct
34°
High: 44°F
Avg: 34°F
Low: 24°F
Nov
26°
High: 36°F
Avg: 26°F
Low: 16°F
Dec
32°F
28°F
Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)

Precipitation

0" 1" 2" 3" 3.4"
1.4"
1.35"
Jan
1.2"
1.24"
Feb
1.6"
1.56"
Mar
2.3"
2.32"
Apr
3.4"
3.40"
May
3.2"
3.19"
Jun
2.2"
2.24"
Jul
2.4"
2.39"
Aug
2.5"
2.55"
Sep
2.0"
2.02"
Oct
1.5"
1.50"
Nov
1.3"
1.28"
Dec

Sunrise / Sunset

4a7a10a1p4p7p10pNoonJanFebMarAprMayJunJulAugSepOctNovDec8.5h10h11.5h13.5h15h15.5h15.5h14h12.5h10.5h9h8.5h
Jan: 7:40 AM – 4:20 PM · 8h 39m
Feb: 6:60 AM – 5:00 PM · 10h 01m
Mar: 6:12 AM – 5:48 PM · 11h 35m
Apr: 5:18 AM – 6:42 PM · 13h 23m
May: 4:33 AM – 7:27 PM · 14h 54m
Jun: 4:08 AM – 7:52 PM · 15h 44m
Jul: 4:18 AM – 7:42 PM · 15h 24m
Aug: 4:58 AM – 7:02 PM · 14h 04m
Sep: 5:50 AM – 6:10 PM · 12h 19m
Oct: 6:43 AM – 5:17 PM · 10h 35m
Nov: 7:29 AM – 4:31 PM · 9h 02m
Dec: 7:52 AM – 4:08 PM · 8h 16m
Daylight Longest: 15h 46m · Shortest: 8h 14m

Nearby Stations

Great Falls Wfo, MT May 12 - September 28 Great Falls 16st, MT May 6 - October 1 Sun Rvr 4 S, MT June 2 - September 10 Carter 14 W, MT May 23 - September 23 Cascade 5 S, MT May 21 - September 19 Fairfield, MT May 13 - September 27

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