Helena, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Helena, a city in Lewis And Clark County, Montana.
Today
63°F
Patchy Fog
Patchy fog and showers and thunderstorms before 9am, then rain between 9am and noon, then showers and thunderstorms. Cloudy. High near 63, with temperatures falling to around 60 in the afternoon. Northwest wind around 5 mph. Chance of precipitation is 100%. New rainfall amounts between a half and three quarters of an inch possible.
7-day forecast for Helena
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 63°F | Patchy Fog | 5 mph NW | 96% |
| Tonight | 45°F | Slight Chance Light Rain then Mostly Cloudy | 3 mph WSW | 15% |
| Sunday | 72°F | Mostly Sunny | 0 to 5 mph ESE | 0% |
| Sunday Night | 44°F | Mostly Clear | 5 mph S | 0% |
| Monday | 76°F | Sunny | 1 to 8 mph S | 0% |
| Monday Night | 46°F | Mostly Clear | 2 to 6 mph WSW | 0% |
| Tuesday | 77°F | Sunny | 1 to 6 mph SSE | 0% |
| Tuesday Night | 47°F | Partly Cloudy | 5 mph SSW | 2% |
| Wednesday | 78°F | Sunny | 1 to 7 mph SSE | 1% |
| Wednesday Night | 48°F | Mostly Clear | 5 mph SSE | 2% |
| Thursday | 79°F | Sunny | 2 to 6 mph SSE | 2% |
| Thursday Night | 48°F | Mostly Clear | 5 mph S | 4% |
| Friday | 77°F | Mostly Sunny | 2 to 7 mph S | 3% |
| Friday Night | 46°F | Mostly Cloudy | 8 mph W | 14% |
Forecast source: National Weather Service (api.weather.gov) for Helena (46.595, -112.019). Updated through the day.
Growing snapshot for Helena
Last spring frost
May 9
First fall frost
Sep 30
Growing season
142 days
More local growing data for Helena: nearby ZIP 59625 weather · frost dates · planting calendar · Montana frost dates
Nearby towns & communities
Canyon Creek
Craig
East Helena
Helena Valley Northeast
Helena Valley Northwest
Helena Valley Southeast
Helena Valley West Central
Helena West Side
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Marysville
Milford Colony
Montana City
Rimini
South Hills
Spokane Creek
Unionville
Wolf Creek
York
Climate data from the nearest NOAA station, Helena Rgnl Ap, Mt (3.6 mi from Helena). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.