Ismay, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Ismay, a town in Custer County, Montana.
This Afternoon
53°F
Partly Sunny
Partly sunny. High near 53, with temperatures falling to around 47 in the afternoon. Northwest wind around 7 mph.
7-day forecast for Ismay
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 53°F | Partly Sunny | 7 mph NW | 0% |
| Tonight | 29°F | Patchy Fog | 5 mph NNE | 0% |
| Thursday | 57°F | Patchy Fog then Mostly Sunny | 7 mph SSE | 0% |
| Thursday Night | 32°F | Mostly Cloudy | 1 to 6 mph SW | 0% |
| Friday | 55°F | Mostly Sunny | 1 to 7 mph W | 0% |
| Friday Night | 36°F | Mostly Clear | 6 mph SW | 0% |
| Saturday | 59°F | Sunny | 3 to 12 mph WSW | 0% |
| Saturday Night | 35°F | Mostly Clear | 5 mph SW | 0% |
| Sunday | 65°F | Mostly Sunny | 5 to 10 mph SSW | 0% |
| Sunday Night | 39°F | Partly Cloudy | 2 to 6 mph W | 0% |
| Monday | 59°F | Mostly Sunny | 2 to 7 mph WNW | 0% |
| Monday Night | 36°F | Partly Cloudy | 3 mph SSW | 2% |
| Tuesday | 61°F | Mostly Sunny | 2 to 8 mph S | 0% |
| Tuesday Night | 39°F | Partly Cloudy | 5 mph SSW | 1% |
Forecast source: National Weather Service (api.weather.gov) for Ismay (46.500, -104.793). Updated through the day.
Growing snapshot for Ismay
Last spring frost
May 22
First fall frost
Sep 15
Growing season
117 days
Hardiness zone
4a
More local growing data for Ismay: nearby ZIP 59336 weather · frost dates · planting calendar · Montana frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Mizpah 4 Nnw, Mt (16.7 mi from Ismay). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 5, 2026.