Westby, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Westby, a town in Sheridan County, Montana.
Tonight
46°F
Cloudy
Cloudy, with a low around 46. East wind around 12 mph, with gusts as high as 18 mph.
7-day forecast for Westby
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 46°F | Cloudy | 12 mph E | 3% |
| Sunday | 63°F | Partly Sunny | 9 to 14 mph SE | 8% |
| Sunday Night | 46°F | Partly Cloudy | 6 to 12 mph SE | 3% |
| Monday | 68°F | Mostly Sunny | 6 to 17 mph S | 0% |
| Monday Night | 48°F | Mostly Clear | 14 to 17 mph S | 0% |
| Tuesday | 71°F | Sunny | 14 to 23 mph S | 0% |
| Tuesday Night | 51°F | Mostly Clear | 14 to 23 mph SE | 1% |
| Wednesday | 74°F | Mostly Sunny | 15 mph S | 6% |
| Wednesday Night | 53°F | Partly Cloudy | 7 to 14 mph S | 10% |
| Thursday | 78°F | Mostly Sunny | 7 to 12 mph S | 7% |
| Thursday Night | 53°F | Mostly Clear | 7 to 12 mph SE | 5% |
| Friday | 78°F | Mostly Sunny | 10 to 23 mph SE | 5% |
| Friday Night | 53°F | Partly Cloudy | 17 to 23 mph SE | 13% |
| Saturday | 69°F | Mostly Sunny | 20 mph S | 13% |
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 Sep 20, 2026.