Johnstown, WY Weather & Growing Conditions
Overnight
29°F
Mostly Cloudy
Mostly cloudy. Low around 29, with temperatures rising to around 33 overnight. West northwest wind around 6 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 29°F | Mostly Cloudy | 6 mph WNW | 0% |
| Wednesday | 50°F | Mostly Cloudy | 3 mph NW | 0% |
| Wednesday Night | 27°F | Partly Cloudy | 2 to 7 mph W | 0% |
| Thursday | 51°F | Mostly Sunny | 2 to 7 mph S | 0% |
| Thursday Night | 31°F | Mostly Cloudy | 2 to 14 mph W | 6% |
| Friday | 52°F | Sunny | 3 to 14 mph WNW | 5% |
| Friday Night | 30°F | Mostly Clear | 6 to 14 mph WNW | 0% |
| Saturday | 54°F | Sunny | 2 to 9 mph SE | 0% |
| Saturday Night | 30°F | Mostly Clear | 3 to 7 mph W | 0% |
| Sunday | 59°F | Sunny | 3 to 7 mph SW | 0% |
| Sunday Night | 35°F | Partly Cloudy | 7 to 13 mph W | 0% |
| Monday | 57°F | Mostly Sunny | 2 to 9 mph WNW | 0% |
| Monday Night | 34°F | Partly Cloudy | 3 to 12 mph WNW | 0% |
| Tuesday | 59°F | Mostly Sunny | 5 to 12 mph WNW | 0% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Johnstown, WY
Last spring frost
May 21
First fall frost
Sep 20
Growing season
119 days
Hardiness zone
5a
Explore more for Johnstown, WY: full frost dates · planting calendar · Wyoming frost dates
Climate data from the nearest NOAA station, Diversion Dam, Wy (4.5 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.