Unionville, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Unionville, a community in Lewis And Clark County, Montana.
Overnight
43°F
Mostly Clear
Mostly clear, with a low around 43. West southwest wind around 1 mph.
7-day forecast for Unionville
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 43°F | Mostly Clear | 1 mph WSW | 0% |
| Tuesday | 72°F | Patchy Smoke | 0 to 6 mph NNE | 0% |
| Tuesday Night | 48°F | Mostly Clear | 2 to 6 mph WNW | 1% |
| Wednesday | 81°F | Sunny | 2 to 6 mph WNW | 0% |
| Wednesday Night | 52°F | Mostly Clear | 3 to 7 mph W | 0% |
| Thursday | 88°F | Sunny | 2 to 10 mph W | 0% |
| Thursday Night | 57°F | Mostly Clear | 3 to 9 mph WSW | 0% |
| Friday | 90°F | Sunny | 2 to 15 mph WSW | 1% |
| Friday Night | 59°F | Mostly Clear | 13 mph W | 0% |
| Saturday | 88°F | Sunny | 3 to 12 mph W | 0% |
| Saturday Night | 59°F | Mostly Clear | 6 to 9 mph W | 0% |
| Sunday | 86°F | Sunny | 2 to 8 mph NW | 1% |
| Sunday Night | 57°F | Mostly Clear | 5 to 8 mph WNW | 1% |
| Monday | 83°F | Sunny | 2 to 7 mph N | 1% |
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 Aug 4, 2026.