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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

WhenTempForecastWindPrecip
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

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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.