Fallon, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Fallon, a community in Prairie County, Montana.
Tonight
56°F
Mostly Cloudy then Chance Showers And Thunderstorms
A chance of showers and thunderstorms between midnight and 5am, then showers and thunderstorms likely. Mostly cloudy, with a low around 56. Northeast wind around 7 mph. Chance of precipitation is 60%.
7-day forecast for Fallon
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 56°F | Mostly Cloudy then Chance Showers And Thunderstorms | 7 mph NE | 56% |
| Saturday | 65°F | Showers And Thunderstorms | 7 to 13 mph NE | 87% |
| Saturday Night | 52°F | Rain Showers | 13 mph ENE | 87% |
| Sunday | 63°F | Rain Showers | 13 mph E | 91% |
| Sunday Night | 49°F | Slight Chance Rain Showers then Mostly Cloudy | 5 to 10 mph ESE | 18% |
| Monday | 71°F | Partly Sunny | 5 to 12 mph SE | 5% |
| Monday Night | 50°F | Mostly Clear | 7 to 13 mph SE | 3% |
| Tuesday | 78°F | Sunny | 6 to 10 mph SSE | 0% |
| Tuesday Night | 52°F | Mostly Clear | 2 to 8 mph SE | 3% |
| Wednesday | 81°F | Mostly Sunny | 2 to 6 mph SSE | 9% |
| Wednesday Night | 52°F | Mostly Clear | 3 mph SE | 10% |
| Thursday | 82°F | Sunny | 2 to 6 mph SE | 3% |
| Thursday Night | 54°F | Mostly Clear | 6 mph SE | 3% |
| Friday | 82°F | Mostly Sunny | 3 to 10 mph SE | 2% |
Forecast source: National Weather Service (api.weather.gov) for Fallon (46.837, -105.127). Updated through the day.
Growing snapshot for Fallon
Last spring frost
May 20
First fall frost
Sep 22
Growing season
124 days
Hardiness zone
4a
More local growing data for Fallon: nearby ZIP 59326 weather · frost dates · planting calendar · Montana frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Mildred 5 N, Mt (4.9 mi from Fallon). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.