Johnstown, CO Weather & Growing Conditions
This Afternoon
58°F
Sunny
Sunny. High near 58, with temperatures falling to around 54 in the afternoon. Northeast wind 5 to 8 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 58°F | Sunny | 5 to 8 mph NE | 0% |
| Tonight | 34°F | Mostly Clear | 3 mph SW | 0% |
| Wednesday | 57°F | Mostly Sunny | 2 mph NNE | 3% |
| Wednesday Night | 35°F | Mostly Cloudy | 5 mph NW | 2% |
| Thursday | 59°F | Sunny | 3 mph S | 0% |
| Thursday Night | 34°F | Partly Cloudy | 2 mph W | 1% |
| Friday | 59°F | Mostly Sunny | 5 mph NE | 5% |
| Friday Night | 34°F | Mostly Clear | 3 mph WSW | 5% |
| Saturday | 61°F | Sunny | 3 mph S | 0% |
| Saturday Night | 33°F | Mostly Clear | 2 mph WSW | 0% |
| Sunday | 66°F | Sunny | 2 mph SSE | 0% |
| Sunday Night | 37°F | Mostly Clear | 3 mph WSW | 0% |
| Monday | 65°F | Sunny | 3 mph SE | 0% |
| Monday Night | 38°F | Partly Cloudy | 3 mph NW | 0% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Johnstown, CO
Last spring frost
May 10
First fall frost
Oct 1
Growing season
142 days
Hardiness zone
5b
Explore more for Johnstown, CO: full frost dates · planting calendar · Colorado frost dates
Climate data from the nearest NOAA station, Loveland 2N, Co (10.5 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 3, 2026.