Johnstown, WY Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Johnstown, a community in Fremont County, Wyoming.
Today
50°F
Sunny
Sunny. High near 50, with temperatures falling to around 45 in the afternoon. South southwest wind around 3 mph.
7-day forecast for Johnstown
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 50°F | Sunny | 3 mph SSW | 0% |
| Tonight | 27°F | Partly Cloudy | 3 mph NW | 0% |
| Wednesday | 49°F | Partly Sunny | 2 mph NE | 0% |
| Wednesday Night | 25°F | Partly Cloudy | 0 to 5 mph SW | 0% |
| Thursday | 52°F | Sunny | 1 to 5 mph SSW | 0% |
| Thursday Night | 30°F | Partly Cloudy | 3 to 10 mph W | 0% |
| Friday | 52°F | Sunny | 2 to 10 mph W | 1% |
| Friday Night | 29°F | Partly Cloudy | 7 to 12 mph W | 2% |
| Saturday | 54°F | Sunny | 3 to 12 mph WNW | 0% |
| Saturday Night | 28°F | Mostly Clear | 6 mph WSW | 0% |
| Sunday | 57°F | Sunny | 3 mph SW | 0% |
| Sunday Night | 32°F | Partly Cloudy | 2 to 7 mph W | 0% |
| Monday | 57°F | Mostly Sunny | 5 mph WNW | 0% |
| Monday Night | 33°F | Mostly Cloudy | 2 to 7 mph WNW | 0% |
Forecast source: National Weather Service (api.weather.gov) for Johnstown (43.114, -108.690). Updated through the day.
Growing snapshot for Johnstown
Last spring frost
May 16
First fall frost
Sep 28
Growing season
133 days
Hardiness zone
5a
More local growing data for Johnstown: nearby ZIP 82510 weather · frost dates · planting calendar · Wyoming frost dates
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Lander
Pavillion
Riverton
Shoshoni
Climate data from the nearest NOAA station, Riverton, Wy (8.1 mi from Johnstown). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 3, 2026.