Longmont, Colorado Weather
Pikas hayfeeding in granite peaks. Day 77 of spring. Read this microseason across nine climate regions →
Longmont weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Overcast——92°50°—
- FridayJun 5Overcast——90°55°-2°
- SaturdayJun 6Drizzle——96°58°+6°
- SundayJun 7Overcast——95°57°-1°
- MondayJun 8Overcast34%—93°58°-2°
- TuesdayJun 9Overcast23%—97°60°+4°
- WednesdayJun 10Light Drizzle10%—101°60°+4°
PM2.5 at 10.6 µg/m³ (AQI 54) with a 0.90 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust. AQI down 26 over the last 6 hours — air quality is improving sharply.
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 10.6 µg/m³ (AQI 54) with a 0.90 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.90
- Wind
- light
- 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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 5:31 AM
- Moonset
- 3:05 PM
- In sign
- ♑︎ Capricorn
Pikas hayfeeding in granite peaks
Longmont at a glance
- Today vs. normal: 17°F below the seasonal normal for this latitude
- Last frost: April 17 (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 4, 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 — Longmont
SPC has placed Longmont in the General Thunderstorms category for severe thunderstorms today.
- TODAYTSTMGeneral Thunderstorms
- TOMORROWNONENo severe risk
- DAY 3NONENo severe risk
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.