Thornton, Colorado Weather
Summer heat breaks with monsoon. Day 43 of summer. Read this microseason across nine climate regions →
Thornton weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayAug 2Overcast——102°67°—
- MondayAug 3Light Drizzle16%0.02″102°75°0°
- TuesdayAug 4Light Drizzle21%—86°63°-16°
- WednesdayAug 5Overcast15%—93°65°+7°
- ThursdayAug 6Clear——97°67°+4°
- FridayAug 7Mostly Clear——101°75°+4°
- SaturdayAug 8Overcast——104°78°+3°
AQI 51 (Moderate), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 9.3 µg/m³ (AQI 51) with a 0.96 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in stagnant 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 9.3 µg/m³ (AQI 51) with a 0.96 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in stagnant air, not road dust.
- PM2.5/PM10
- 0.96
- 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).
Red sky at night, sailor's delight.
- Moonrise
- 9:44 PM
- Moonset
- 10:07 AM
- In sign
- ♓︎ Pisces
Summer heat breaks with monsoon
Thornton at a glance
- Today vs. normal: 15°F above the seasonal normal for this latitude
- Last frost: April 16 (climatological average for this latitude)
- Microseason: Aug 1–5
- Planting window: Sow fall peas. Start kale and collard seedlings for fall.
ZIP code: 80241
16-Day Forecast — Thornton
- Sun102°67°1%
- Mon102°75°16%
- Tue86°63°21%
- Wed93°65°15%
- Thu97°67°8%
- Fri101°75°2%
- Sat104°78°3%
- Sun101°78°12%
- Mon104°79°19%
- Tue101°78°31%
- Wed96°77°45%
- Thu92°73°45%
- Fri99°75°65%
- Sat94°68°65%
- Sun97°75°52%
- Mon99°74°54%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Thornton
Right now in the garden
Peak growing season
As of August 2, 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 — Thornton
SPC includes Thornton in the general thunderstorm area tomorrow — no severe risk, but storms are possible.
- TODAYNONENo severe risk
- 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.
Sun & seasons in Thornton
Thornton sits in Adams County, where the year’s longest day runs 15h 0m of daylight and its shortest just 9h 20m — a swing of +5h 40m between the June and December solstices. Clocks spring forward on Sunday, March 8, 2026 and fall back on Sunday, November 1, 2026.
Denver, the state’s largest city, lies about 11 miles to the SSE. The nearest town Thornton tracks is Denver, roughly 11 miles to the SSE.
Air quality in Thornton’s county has trended dirtier since 2020; its cleanest year on record was 2020 (median AQI 49). See the full air-quality history for Thornton.
ZIP codes in Thornton
- 80260
- 80233
- 80241
- 80640
- 80023
- 80229
- 80602
- 80614