Frost Dates for Lewistown 11ese, 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 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 25
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 20

Hard Freeze (28°F / -2°C)

Last Spring Hard Freeze May 7
First Fall Hard Freeze October 5
47.01°N, -109.22°W © OpenStreetMap

Growing Season

129 Days May 19 to September 25

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 5b

Learn more

Temperature

10° 30° 50° 70°
24°
High: 33°
Avg: 24°
Low: 15°
Jan
24°
High: 33°
Avg: 24°
Low: 15°
Feb
31°
High: 41°
Avg: 31°
Low: 22°
Mar
39°
High: 49°
Avg: 39°
Low: 29°
Apr
48°
High: 59°
Avg: 48°
Low: 38°
May
56°
High: 67°
Avg: 56°
Low: 46°
Jun
66°
High: 77°
Avg: 66°
Low: 54°
Jul
66°
High: 78°
Avg: 66°
Low: 53°
Aug
56°
High: 67°
Avg: 56°
Low: 44°
Sep
43°
High: 53°
Avg: 43°
Low: 34°
Oct
32°
High: 39°
Avg: 32°
Low: 24°
Nov
25°
High: 34°
Avg: 25°
Low: 17°
Dec
32°F
28°F
Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)

Precipitation

0" 2" 4" 5.9"
2.9"
2.89"
Jan
2.7"
2.66"
Feb
3.7"
3.68"
Mar
4.7"
4.67"
Apr
5.3"
5.33"
May
5.3"
5.28"
Jun
4.2"
4.17"
Jul
4.6"
4.59"
Aug
5.9"
5.88"
Sep
5.0"
5.03"
Oct
3.1"
3.12"
Nov
2.9"
2.88"
Dec

Sunrise / Sunset

4a7a10a1p4p7p10pNoonJanFebMarAprMayJunJulAugSepOctNovDec9h10h12h13h15h16h15h14h12h11h9h8h
Jan: 7:39 AM – 4:21 PM · 8h 43m
Feb: 6:59 AM – 5:01 PM · 10h 03m
Mar: 6:12 AM – 5:48 PM · 11h 36m
Apr: 5:19 AM – 6:41 PM · 13h 22m
May: 4:34 AM – 7:26 PM · 14h 51m
Jun: 4:10 AM – 7:50 PM · 15h 40m
Jul: 4:20 AM – 7:40 PM · 15h 20m
Aug: 4:59 AM – 7:01 PM · 14h 02m
Sep: 5:50 AM – 6:10 PM · 12h 19m
Oct: 6:42 AM – 5:18 PM · 10h 36m
Nov: 7:27 AM – 4:33 PM · 9h 05m
Dec: 7:50 AM – 4:10 PM · 8h 19m
Daylight Longest: 15h 42m · Shortest: 8h 18m

Nearby Stations

Lewistown, MT May 14 - September 28 Lewistown 11 Sse, MT May 31 - September 14 Lewistown Muni AP, MT May 23 - September 21 Grass Range, MT May 20 - September 24 Judith Gap 13 E, MT June 3 - September 15 Ryegate 18 Nnw, MT May 26 - September 18

Plan Your Garden with Planter

Now that you know your frost dates, use Planter to plan your veggie garden! Planter is an easy drag-and-drop garden planner with personalized planting schedules.

Try Planter For Free

Available everywhere: iOS, Android, web, and more!

Planter app garden planner preview