Today | Weather | Friday, September 18, 2026

Weather in Thornton, Colorado

01:36 PM
Now
Cloudy Weather
82° F
Feels Like 82°
Precipitation 20 %
Wind 8 mph
UV Index (0 - 11+) 2
Humidity 35 %
Today
Sunny with a Chance of Thunderstorms
Day 84°
Night 55°
Precipitation 57 %
Wind 6 mph
UV Index (0 - 11+) 5

Thornton Weather Forecast Updated

1 minute ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (September 18, 2025)
Night

Day

72°

Night

48°

Wind

5 mph

Precipitation

1 %

Air Quality in Thornton

NOW
26 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 0.5 µg/m³
PM10 0.5 µg/m³
O3 0.028 ppm
NO2 0.1 ppb
SO2 0 ppb
CO 0.08 ppm
NH3 0.06 µg/m³
NO 0.03 µg/m³
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide
NH3 – Ammonia
NO – Nitric oxide

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Show raw pollutant concentrations (µg/m³)
PM2.50.5 µg/m³
PM100.5 µg/m³
O354.33 µg/m³
NO20.16 µg/m³
SO20.02 µg/m³
CO92.84 µg/m³
NH30.06 µg/m³
NO0.03 µg/m³