Harman US

Grass Range, MT Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Grass Range, a town in Fergus County, Montana.

Tonight
53°F
Slight Chance Light Rain then Showers And Thunderstorms Likely
A slight chance of rain between 10pm and midnight, then showers and thunderstorms likely. Cloudy, with a low around 53. North wind 6 to 9 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.

7-day forecast for Grass Range

WhenTempForecastWindPrecip
Tonight 53°F Slight Chance Light Rain then Showers And Thunderstorms Likely 6 to 9 mph N 65%
Saturday 59°F Rain then Showers And Thunderstorms 8 to 12 mph N 84%
Saturday Night 51°F Rain 6 to 9 mph N 79%
Sunday 63°F Light Rain Likely 7 mph NNE 66%
Sunday Night 48°F Mostly Cloudy 5 to 8 mph SE 9%
Monday 74°F Mostly Sunny 5 to 12 mph SSE 0%
Monday Night 51°F Mostly Clear 8 to 13 mph S 0%
Tuesday 79°F Mostly Sunny 6 mph WNW 0%
Tuesday Night 54°F Partly Cloudy 7 mph S 2%
Wednesday 79°F Sunny 7 mph WSW 2%
Wednesday Night 54°F Mostly Clear 8 mph S 1%
Thursday 80°F Sunny 6 to 10 mph S 2%
Thursday Night 55°F Mostly Clear 10 mph S 3%
Friday 81°F Mostly Sunny 7 to 10 mph SSW 1%

Forecast source: National Weather Service (api.weather.gov) for Grass Range (47.026, -108.803). Updated through the day.

Growing snapshot for Grass Range

Last spring frost
May 20
First fall frost
Sep 24
Growing season
126 days
Hardiness zone
4b

More local growing data for Grass Range: nearby ZIP 59032 weather · frost dates · planting calendar · Montana frost dates

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Climate data from the nearest NOAA station, Grass Range, Mt (4.7 mi from Grass Range). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.