Big Arm, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Big Arm, a community in Lake County, Montana.
This Afternoon
72°F
Mostly Sunny
Mostly sunny, with a high near 72. South wind 2 to 7 mph.
7-day forecast for Big Arm
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 72°F | Mostly Sunny | 2 to 7 mph S | 2% |
| Tonight | 55°F | Mostly Cloudy | 1 mph WNW | 5% |
| Saturday | 71°F | Mostly Sunny | 2 mph NE | 3% |
| Saturday Night | 53°F | Partly Cloudy | 1 mph SE | 0% |
| Sunday | 72°F | Sunny | 0 to 3 mph SSE | 0% |
| Sunday Night | 55°F | Clear | 1 mph ENE | 0% |
| Monday | 74°F | Sunny | 0 to 3 mph S | 0% |
| Monday Night | 55°F | Mostly Clear | 2 mph E | 0% |
| Tuesday | 73°F | Sunny | 2 mph S | 0% |
| Tuesday Night | 55°F | Partly Cloudy | 2 mph ENE | 1% |
| Wednesday | 71°F | Sunny | 0 to 5 mph SSW | 1% |
| Wednesday Night | 54°F | Partly Cloudy | 2 mph WNW | 3% |
| Thursday | 72°F | Mostly Sunny | 2 mph ENE | 2% |
| Thursday Night | 55°F | Partly Cloudy | 1 mph N | 1% |
Forecast source: National Weather Service (api.weather.gov) for Big Arm (47.794, -114.270). Updated through the day.
Growing snapshot for Big Arm
Last spring frost
May 15
First fall frost
Sep 28
Growing season
134 days
Hardiness zone
6a
More local growing data for Big Arm: nearby ZIP 59910 weather · frost dates · planting calendar · Montana frost dates
Nearby towns & communities
Bear Dance
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Dayton
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Finley Point
Jette
Kerr
Kicking Horse
Kings Point
Lake Mary Ronan
Lindisfarne
Niarada
Pablo
Polson
Ravalli
Rocky Point
Rollins
Ronan
St. Ignatius
Swan Lake
Turtle Lake
Climate data from the nearest NOAA station, Skq Dam, Mt (9.9 mi from Big Arm). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 18, 2026.