Frost Dates for St. Mary 1 Ssw, MT

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. June 3
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 8
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 June 10
First Fall Frost September 1

Hard Freeze (28°F / -2°C)

Last Spring Hard Freeze May 14
First Fall Hard Freeze September 25
48.74°N, -113.43°W © OpenStreetMap

Growing Season

97 Days June 3 to September 8

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 4a

Learn more

Temperature

10° 30° 50° 70°
23°
High: 32°
Avg: 23°
Low: 15°
Jan
23°
High: 31°
Avg: 23°
Low: 15°
Feb
29°
High: 38°
Avg: 29°
Low: 20°
Mar
37°
High: 46°
Avg: 37°
Low: 28°
Apr
46°
High: 56°
Avg: 46°
Low: 35°
May
52°
High: 63°
Avg: 52°
Low: 42°
Jun
60°
High: 73°
Avg: 60°
Low: 46°
Jul
59°
High: 73°
Avg: 59°
Low: 45°
Aug
51°
High: 63°
Avg: 51°
Low: 39°
Sep
40°
High: 49°
Avg: 40°
Low: 32°
Oct
31°
High: 37°
Avg: 31°
Low: 25°
Nov
24°
High: 31°
Avg: 24°
Low: 17°
Dec
32°F
28°F
Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)

Precipitation

0" 1" 2" 3" 3.3"
2.5"
2.48"
Jan
2.4"
2.36"
Feb
2.8"
2.79"
Mar
2.9"
2.86"
Apr
3.3"
3.29"
May
3.1"
3.07"
Jun
1.9"
1.93"
Jul
2.5"
2.48"
Aug
3.2"
3.18"
Sep
3.3"
3.26"
Oct
2.7"
2.69"
Nov
2.5"
2.48"
Dec

Sunrise / Sunset

4a7a10a1p4p7p10pNoonJanFebMarAprMayJunJulAugSepOctNovDec8h10h12h13h15h16h16h14h12h11h9h8h
Jan: 7:45 AM – 4:15 PM · 8h 29m
Feb: 7:02 AM – 4:58 PM · 9h 55m
Mar: 6:13 AM – 5:47 PM · 11h 34m
Apr: 5:16 AM – 6:44 PM · 13h 27m
May: 4:29 AM – 7:31 PM · 15h 03m
Jun: 4:02 AM – 7:58 PM · 15h 55m
Jul: 4:13 AM – 7:47 PM · 15h 34m
Aug: 4:55 AM – 7:05 PM · 14h 10m
Sep: 5:50 AM – 6:10 PM · 12h 20m
Oct: 6:44 AM – 5:16 PM · 10h 31m
Nov: 7:33 AM – 4:27 PM · 8h 53m
Dec: 7:58 AM – 4:02 PM · 8h 04m
Daylight Longest: 15h 57m · Shortest: 8h 03m

Nearby Stations

St Mary, MTJune 12 - September 5 Carway, CanadaJune 8 - August 22 E Glacier, MTJune 8 - September 5 W Glacier, MT May 18 - September 20 Waterton Park Gate, Canada May 30 - September 2 Cardston, Canada May 18 - September 19

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