Unionville, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Unionville, a community in Lewis And Clark County, Montana.
Tonight
51°F
Showers And Thunderstorms
Showers and thunderstorms. Cloudy, with a low around 51. North northwest wind 3 to 7 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.
7-day forecast for Unionville
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 51°F | Showers And Thunderstorms | 3 to 7 mph NNW | 98% |
| Saturday | 56°F | Showers And Thunderstorms | 7 mph N | 96% |
| Saturday Night | 46°F | Chance Light Rain | 5 mph W | 33% |
| Sunday | 66°F | Mostly Sunny | 5 mph NW | 1% |
| Sunday Night | 45°F | Mostly Clear | 5 mph S | 0% |
| Monday | 71°F | Sunny | 2 to 6 mph SW | 0% |
| Monday Night | 47°F | Mostly Clear | 3 to 7 mph W | 0% |
| Tuesday | 71°F | Sunny | 5 mph WNW | 1% |
| Tuesday Night | 48°F | Partly Cloudy | 5 mph WSW | 1% |
| Wednesday | 71°F | Sunny | 6 mph SW | 2% |
| Wednesday Night | 48°F | Mostly Clear | 5 mph WSW | 3% |
| Thursday | 73°F | Sunny | 5 mph S | 1% |
| Thursday Night | 50°F | Partly Cloudy | 7 mph SSE | 1% |
| Friday | 73°F | Mostly Sunny | 7 mph SSW | 2% |
Forecast source: National Weather Service (api.weather.gov) for Unionville (46.546, -112.085). Updated through the day.
Growing snapshot for Unionville
Last spring frost
May 9
First fall frost
Sep 30
Growing season
142 days
Hardiness zone
5a
More local growing data for Unionville: nearby ZIP 59623 weather · frost dates · planting calendar · Montana frost dates
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Climate data from the nearest NOAA station, Helena Rgnl Ap, Mt (3.8 mi from Unionville). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.