Johnstown, WY Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Johnstown, a community in Fremont County, Wyoming.
This Afternoon
75°F
Showers And Thunderstorms Likely
Showers and thunderstorms likely. Mostly cloudy. High near 75, with temperatures falling to around 71 in the afternoon. South wind around 8 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast for Johnstown
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 75°F | Showers And Thunderstorms Likely | 8 mph S | 62% |
| Tonight | 50°F | Chance Showers And Thunderstorms then Slight Chance Showers And Thunderstorms | 3 to 8 mph NW | 48% |
| Saturday | 69°F | Patchy Fog then Slight Chance Showers And Thunderstorms | 2 to 9 mph NNW | 47% |
| Saturday Night | 45°F | Showers And Thunderstorms Likely | 2 to 10 mph WNW | 74% |
| Sunday | 65°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 2 to 6 mph NW | 27% |
| Sunday Night | 44°F | Partly Cloudy | 1 to 6 mph W | 5% |
| Monday | 70°F | Sunny | 2 to 6 mph NNE | 1% |
| Monday Night | 46°F | Mostly Clear | 5 to 8 mph NNW | 1% |
| Tuesday | 75°F | Mostly Sunny | 5 mph N | 3% |
| Tuesday Night | 49°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 5 to 8 mph NW | 19% |
| Wednesday | 76°F | Sunny | 3 to 7 mph N | 5% |
| Wednesday Night | 48°F | Mostly Clear | 8 mph NW | 4% |
| Thursday | 79°F | Sunny | 6 mph N | 2% |
| Thursday Night | 49°F | Partly Cloudy | 8 mph NNW | 6% |
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
Nearby towns & communities
Arapahoe
Atlantic City
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Crowheart
Dubois
Ethete
Fort Washakie
Hudson
Jeffrey City
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 Sep 19, 2026.