Big Arm, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Big Arm, a community in Lake County, Montana.
Tonight
33°F
Mostly Cloudy
Mostly cloudy, with a low around 33. Wind around 0 mph.
7-day forecast for Big Arm
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 33°F | Mostly Cloudy | 0 mph | 0% |
| Wednesday | 46°F | Mostly Sunny | 2 mph NNW | 0% |
| Wednesday Night | 33°F | Partly Cloudy | 1 mph SW | 1% |
| Thursday | 45°F | Partly Sunny | 1 to 6 mph SSW | 10% |
| Thursday Night | 35°F | Mostly Cloudy | 5 mph SSW | 6% |
| Friday | 49°F | Partly Sunny | 2 to 7 mph SSW | 12% |
| Friday Night | 39°F | Mostly Cloudy | 2 to 7 mph SSW | 12% |
| Saturday | 53°F | Partly Sunny | 2 mph SSW | 3% |
| Saturday Night | 40°F | Mostly Cloudy then Slight Chance Light Rain | 1 mph SSW | 19% |
| Sunday | 55°F | Slight Chance Light Rain | 1 to 13 mph SSW | 19% |
| Sunday Night | 40°F | Mostly Cloudy | 0 to 8 mph SW | 12% |
| Monday | 51°F | Partly Sunny then Slight Chance Light Rain | 1 mph WNW | 16% |
| Monday Night | 40°F | Slight Chance Light Rain | 1 mph SW | 17% |
| Tuesday | 53°F | Slight Chance Light Rain | 3 mph SSW | 17% |
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
Charlo
Dayton
Elmo
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 Nov 4, 2026.