Unionville, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Unionville, a community in Lewis And Clark County, Montana.
This Afternoon
44°F
Mostly Sunny
Mostly sunny. High near 44, with temperatures falling to around 38 in the afternoon. South southeast wind around 3 mph.
7-day forecast for Unionville
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 44°F | Mostly Sunny | 3 mph SSE | 0% |
| Tonight | 29°F | Mostly Cloudy | 2 to 6 mph SW | 0% |
| Wednesday | 44°F | Mostly Sunny | 2 mph WNW | 0% |
| Wednesday Night | 28°F | Mostly Clear | 1 to 6 mph SW | 0% |
| Thursday | 44°F | Mostly Sunny | 5 mph WSW | 4% |
| Thursday Night | 31°F | Partly Cloudy | 3 to 8 mph WSW | 4% |
| Friday | 46°F | Mostly Sunny | 6 to 9 mph SW | 6% |
| Friday Night | 34°F | Mostly Cloudy | 6 to 18 mph SW | 6% |
| Saturday | 48°F | Mostly Sunny | 3 to 12 mph SW | 0% |
| Saturday Night | 36°F | Partly Cloudy | 3 to 10 mph SSW | 0% |
| Sunday | 53°F | Mostly Sunny | 5 to 9 mph SSW | 3% |
| Sunday Night | 37°F | Mostly Cloudy | 5 to 9 mph SW | 3% |
| Monday | 49°F | Partly Sunny | 2 to 6 mph SSW | 2% |
| Monday Night | 38°F | Mostly Cloudy | 2 to 9 mph SW | 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 Nov 3, 2026.