Westby, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Westby, a town in Sheridan County, Montana.
Overnight
44°F
Partly Cloudy
Partly cloudy, with a low around 44. West wind around 9 mph.
7-day forecast for Westby
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 44°F | Partly Cloudy | 9 mph W | 0% |
| Tuesday | 72°F | Mostly Sunny | 9 to 17 mph W | 0% |
| Tuesday Night | 49°F | Partly Cloudy | 6 to 16 mph W | 2% |
| Wednesday | 80°F | Partly Sunny | 9 to 21 mph SW | 6% |
| Wednesday Night | 52°F | Partly Cloudy | 6 to 21 mph W | 6% |
| Thursday | 83°F | Sunny | 6 to 15 mph W | 2% |
| Thursday Night | 53°F | Mostly Clear | 8 to 15 mph NW | 2% |
| Friday | 80°F | Sunny | 9 mph N | 1% |
| Friday Night | 52°F | Mostly Clear | 7 to 10 mph NE | 6% |
| Saturday | 81°F | Mostly Sunny | 7 to 13 mph NE | 6% |
| Saturday Night | 53°F | Partly Cloudy | 9 to 14 mph NE | 3% |
| Sunday | 79°F | Partly Sunny | 8 to 16 mph NE | 11% |
| Sunday Night | 54°F | Slight Chance Showers And Thunderstorms | 10 to 16 mph NE | 24% |
| Monday | 78°F | Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms | 10 to 15 mph NE | 23% |
Forecast source: National Weather Service (api.weather.gov) for Westby (48.870, -104.057). Updated through the day.
Growing snapshot for Westby
Last spring frost
May 18
First fall frost
Sep 21
Growing season
125 days
Hardiness zone
3b
More local growing data for Westby: nearby ZIP 59275 weather · frost dates · planting calendar · Montana frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Westby, Mt (4.8 mi from Westby). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.