Frost Dates for Circle, 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. May 17
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 22
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 23
First Fall Frost September 17

Hard Freeze (28°F / -2°C)

Last Spring Hard Freeze May 6
First Fall Hard Freeze October 1
47.41°N, -105.60°W © OpenStreetMap

Growing Season

128 Days May 17 to September 22

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

0° 30° 60° 90°
18°
High: 29°
Avg: 18°
Low: 8°
Jan
22°
High: 33°
Avg: 22°
Low: 12°
Feb
34°
High: 46°
Avg: 34°
Low: 22°
Mar
45°
High: 58°
Avg: 45°
Low: 32°
Apr
55°
High: 68°
Avg: 55°
Low: 42°
May
64°
High: 78°
Avg: 64°
Low: 51°
Jun
72°
High: 87°
Avg: 72°
Low: 57°
Jul
71°
High: 87°
Avg: 71°
Low: 55°
Aug
60°
High: 76°
Avg: 60°
Low: 45°
Sep
46°
High: 59°
Avg: 46°
Low: 33°
Oct
32°
High: 43°
Avg: 32°
Low: 21°
Nov
21°
High: 32°
Avg: 21°
Low: 11°
Dec
32°F
28°F
Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)

Precipitation

0" 2" 4" 6" 6.4"
1.6"
1.55"
Jan
1.6"
1.55"
Feb
2.3"
2.33"
Mar
4.0"
4.01"
Apr
5.8"
5.76"
May
6.0"
6.00"
Jun
5.8"
5.78"
Jul
6.4"
6.42"
Aug
6.0"
5.98"
Sep
4.0"
4.01"
Oct
1.8"
1.82"
Nov
1.6"
1.55"
Dec

Sunrise / Sunset

4a7a10a1p4p7p10pNoonJanFebMarAprMayJunJulAugSepOctNovDec9h10h12h13h15h16h15h14h12h11h9h8h
Jan: 7:40 AM – 4:20 PM · 8h 40m
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 23m
Aug: 4:58 AM – 7:02 PM · 14h 04m
Sep: 5:50 AM – 6:10 PM · 12h 19m
Oct: 6:42 AM – 5:18 PM · 10h 35m
Nov: 7:29 AM – 4:31 PM · 9h 02m
Dec: 7:52 AM – 4:08 PM · 8h 16m
Daylight Longest: 15h 45m · Shortest: 8h 15m

Nearby Stations

Brockway 3 Wsw, MT May 20 - September 19 Terry 21 Nnw, MT May 26 - September 17 Vida 6 Ne, MT May 16 - September 22 Terry, MTMay 12 - September 28 Glendive, MTMay 3 - October 4 Wolf Point Intl AP, MT May 16 - September 20

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