Johnstown, Colorado Weather
Pikas hayfeeding in granite peaks. Day 78 of spring. Read this microseason across nine climate regions →
Johnstown weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 5Overcast——90°54°—
- SaturdayJun 6Overcast——96°56°+6°
- SundayJun 7Overcast——94°59°-2°
- MondayJun 8Overcast14%—93°56°-1°
- TuesdayJun 9Overcast——99°63°+6°
- WednesdayJun 10Overcast——98°57°-1°
- ThursdayJun 11Overcast14%—82°52°-16°
AQI 45 (Good), driven by PM2.5. AQI down 10 over the last 6 hours (steady decline since this morning). PM2.5 at 8.1 µg/m³, PM10 at 10.1 µg/m³ — typical background levels with no transport signature.
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 8.1 µg/m³, PM10 at 10.1 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.80
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- background
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).
The higher the clouds, the finer the weather.
- Moonrise
- 6:02 AM
- Moonset
- 4:09 PM
- In sign
- ♒︎ Aquarius
Pikas hayfeeding in granite peaks
Johnstown at a glance
- Today vs. normal: 16°F below the seasonal normal for this latitude
- Last frost: April 18 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Warm-season window is open
As of June 5, the last spring frost has passed for most years. Transplant tomatoes, peppers, eggplants, basil, and cucurbits (cucumbers, squash, melons) now. Direct-sow beans and corn into warm soil.
SPC Convective Outlook
Storm Prediction Center — Johnstown
SPC has placed Johnstown in the General Thunderstorms category for severe thunderstorms today.
- 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.