Thornton, Colorado Weather
Pikas hayfeeding in granite peaks. Day 77 of spring. Read this microseason across nine climate regions →
Thornton weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast18%—82°54°—
- ThursdayJun 4Overcast——90°54°+8°
- FridayJun 5Clear——89°60°-1°
- SaturdayJun 6Drizzle——95°67°+6°
- SundayJun 7Overcast22%—94°66°-1°
- MondayJun 8Overcast40%—94°67°0°
- TuesdayJun 9Light Drizzle36%—99°71°+5°
Ozone at AQI 63. AQI up 24 in the last 6 hours — air quality is degrading. Overcast through the UV peak window (cloud cover ~72%) — afternoon ozone should stay flat.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 63. Overcast through the UV peak window (cloud cover ~72%) — afternoon ozone should stay flat.
- Present
- AQI 63
- UV peak
- 0.2 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 8
PM × Wind × Precip
PM2.5/PM10 ratio 0.64 with 12 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.64
- Wind
- breezy
- Recent rain
- 0h in last 6h
- Pattern
- transport
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
- 5:30 AM
- Moonset
- 3:05 PM
- In sign
- ♑︎ Capricorn
Pikas hayfeeding in granite peaks
Thornton at a glance
- Today vs. normal: 73°F — typical for the season
- Last frost: April 16 (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 — Thornton
SPC has placed Thornton in the General Thunderstorms category for severe thunderstorms today.
- TODAYTSTMGeneral Thunderstorms
- TOMORROWTSTMGeneral Thunderstorms
- 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.