Helena, MT Weather & Growing Conditions
Tonight
29°F
Partly Cloudy
Partly cloudy. Low around 29, with temperatures rising to around 32 overnight. West southwest wind 0 to 6 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 29°F | Partly Cloudy | 0 to 6 mph WSW | 0% |
| Wednesday | 47°F | Mostly Sunny | 2 mph NNW | 0% |
| Wednesday Night | 28°F | Mostly Clear | 1 to 6 mph SSW | 0% |
| Thursday | 48°F | Mostly Sunny | 5 mph SW | 4% |
| Thursday Night | 31°F | Partly Cloudy | 3 to 9 mph SW | 4% |
| Friday | 50°F | Mostly Sunny | 7 mph SW | 6% |
| Friday Night | 35°F | Partly Cloudy | 6 to 16 mph SW | 6% |
| Saturday | 51°F | Mostly Sunny | 3 to 8 mph SSW | 0% |
| Saturday Night | 35°F | Partly Cloudy | 3 to 8 mph SSW | 0% |
| Sunday | 57°F | Mostly Sunny | 6 mph SSW | 2% |
| Sunday Night | 37°F | Mostly Cloudy | 2 to 6 mph SW | 3% |
| Monday | 53°F | Partly Sunny | 3 mph SSW | 2% |
| Monday Night | 37°F | Mostly Cloudy | 2 to 6 mph SW | 2% |
| Tuesday | 56°F | Mostly Sunny | 6 mph SSW | 3% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Helena, MT
Last spring frost
May 9
First fall frost
Sep 30
Growing season
142 days
Hardiness zone
5a
Explore more for Helena, MT: full frost dates · planting calendar · Montana frost dates
Climate data from the nearest NOAA station, Helena Rgnl Ap, Mt (3.8 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.