Johnstown, Colorado Weather
Monsoon storms drench the south. Day 15 of summer. Read this microseason across nine climate regions →
Johnstown weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 5Mostly Clear——92°57°—
- MondayJul 6Overcast——95°60°+3°
- TuesdayJul 7Light Drizzle32%—99°67°+4°
- WednesdayJul 8Light Drizzle59%—97°63°-2°
- ThursdayJul 9Light Drizzle44%—99°60°+2°
- FridayJul 10Overcast12%—98°61°-1°
- SaturdayJul 11Clear——100°61°+2°
AQI 48 (Good), driven by PM2.5. AQI down 55 over the last 6 hours — air quality is improving sharply. PM2.5 at 12.0 µg/m³ (AQI 56) with a 0.90 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in calm air, not road dust.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
PM × Wind × Precip
PM2.5 at 12.0 µg/m³ (AQI 56) with a 0.90 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.90
- Wind
- calm
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 11:19 PM
- Moonset
- 11:14 AM
- In sign
- ♓︎ Pisces
Monsoon storms drench the south
Johnstown at a glance
- Today vs. normal: 10°F below the seasonal normal for this latitude
- Last frost: April 18 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP code: 80534
15-Day Forecast — Johnstown
- Sun92°57°3%
- Mon95°60°1%
- Tue99°67°32%
- Wed97°63°59%
- Thu99°60°44%
- Fri98°61°12%
- Sat100°61°5%
- Sun104°64°3%
- Mon110°64°7%
- Tue103°71°15%
- Wed111°65°24%
- Thu105°67°30%
- Fri102°65°38%
- Sat106°65°39%
- Sun94°68°39%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 5, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
SPC Convective Outlook
Storm Prediction Center — Johnstown
SPC includes Johnstown in the general thunderstorm area today — no severe risk, but storms are possible.
- TODAYTSTMGeneral Thunderstorms
- TOMORROWTSTMGeneral Thunderstorms
- DAY 3TSTMGeneral Thunderstorms
Thunderstorms possible. Not severe, but capable of producing lightning and brief heavy rain.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.
ZIP codes in Johnstown
- 80534