Helena, MT Weather & Growing Conditions
Tonight
54°F
Showers And Thunderstorms
Showers and thunderstorms. Cloudy. Low around 54, with temperatures rising to around 57 overnight. West wind 3 to 8 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 54°F | Showers And Thunderstorms | 3 to 8 mph W | 97% |
| Saturday | 59°F | Rain then Showers And Thunderstorms Likely | 7 mph NNW | 96% |
| Saturday Night | 50°F | Chance Light Rain | 1 to 5 mph WSW | 32% |
| Sunday | 72°F | Mostly Sunny | 1 to 5 mph SSE | 1% |
| Sunday Night | 49°F | Mostly Clear | 5 mph S | 0% |
| Monday | 76°F | Sunny | 2 to 7 mph SSW | 0% |
| Monday Night | 50°F | Mostly Clear | 6 mph W | 0% |
| Tuesday | 77°F | Sunny | 2 to 6 mph SE | 1% |
| Tuesday Night | 52°F | Mostly Clear | 5 mph SW | 1% |
| Wednesday | 77°F | Sunny | 2 to 7 mph SW | 1% |
| Wednesday Night | 52°F | Mostly Clear | 5 mph WSW | 3% |
| Thursday | 78°F | Sunny | 2 to 6 mph SSE | 1% |
| Thursday Night | 53°F | Partly Cloudy | 6 mph SE | 2% |
| Friday | 78°F | Mostly Sunny | 3 to 7 mph SSW | 2% |
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 Sep 19, 2026.