Sweet Grass, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Sweet Grass, a community in Toole County, Montana.
Tonight
48°F
Mostly Cloudy
Mostly cloudy, with a low around 48. North wind around 6 mph.
7-day forecast for Sweet Grass
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 48°F | Mostly Cloudy | 6 mph N | 0% |
| Saturday | 68°F | Mostly Sunny | 3 to 10 mph SW | 0% |
| Saturday Night | 47°F | Partly Cloudy | 13 mph SSE | 0% |
| Sunday | 71°F | Sunny | 13 to 16 mph S | 0% |
| Sunday Night | 48°F | Mostly Clear | 13 to 16 mph S | 0% |
| Monday | 76°F | Sunny | 14 mph S | 0% |
| Monday Night | 49°F | Mostly Clear | 8 to 12 mph SW | 0% |
| Tuesday | 71°F | Mostly Sunny | 9 mph WNW | 0% |
| Tuesday Night | 49°F | Partly Cloudy | 5 to 9 mph S | 1% |
| Wednesday | 72°F | Mostly Sunny | 9 to 13 mph SW | 0% |
| Wednesday Night | 49°F | Partly Cloudy | 10 mph SW | 3% |
| Thursday | 71°F | Mostly Sunny | 10 mph SSW | 3% |
| Thursday Night | 50°F | Partly Cloudy | 12 mph S | 2% |
| Friday | 71°F | Mostly Sunny | 12 mph SSW | 4% |
Forecast source: National Weather Service (api.weather.gov) for Sweet Grass (48.993, -111.967). Updated through the day.
Growing snapshot for Sweet Grass
Last spring frost
May 17
First fall frost
Sep 25
Growing season
129 days
Hardiness zone
4a
More local growing data for Sweet Grass: nearby ZIP 59482 weather · frost dates · planting calendar · Montana frost dates
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Sunburst
Climate data from the nearest NOAA station, Sunburst 8 E, Mt (5.9 mi from Sweet Grass). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.