Hourly Weather Forecast for Thornton, Colorado

Hourly Weather | Today › Wednesday, March 18, 2026

Active Weather Warnings

Red Flag Warning

Thornton, Colorado

6 PM

77°

Feels Like 73°

Humidity: 11%

UV Index: 1

Wind: 15 mph

7 PM

73°

Feels Like 70°

Humidity: 13%

UV Index: 0

Wind: 13 mph

8 PM

70°

Feels Like 66°

Humidity: 15%

UV Index: 0

Wind: 9 mph

9 PM

66°

Feels Like 64°

Humidity: 18%

UV Index: 0

Wind: 8 mph

10 PM

63°

Feels Like 61°

Humidity: 20%

UV Index: 0

Wind: 8 mph

11 PM

59°

Feels Like 55°

Humidity: 23%

UV Index: 0

Wind: 8 mph

Hourly Air Quality Forecast - AQI (US EPA)

6 PM

39 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 0.59 µg/m³
PM₁₀: 0.74 µg/m³
O₃: 0.042 ppm
NO₂: 0.1 ppb
SO₂: 0 ppb
CO: 0.07 ppm

Health Recommendations:

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

7 PM

37 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 0.64 µg/m³
PM₁₀: 0.83 µg/m³
O₃: 0.040 ppm
NO₂: 0.6 ppb
SO₂: 0 ppb
CO: 0.08 ppm

Health Recommendations:

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

8 PM

33 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 0.78 µg/m³
PM₁₀: 0.99 µg/m³
O₃: 0.035 ppm
NO₂: 1.2 ppb
SO₂: 0 ppb
CO: 0.09 ppm

Health Recommendations:

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

9 PM

29 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 0.92 µg/m³
PM₁₀: 1.15 µg/m³
O₃: 0.032 ppm
NO₂: 1.7 ppb
SO₂: 0 ppb
CO: 0.09 ppm

Health Recommendations:

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

10 PM

26 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 0.99 µg/m³
PM₁₀: 1.23 µg/m³
O₃: 0.028 ppm
NO₂: 1.9 ppb
SO₂: 0 ppb
CO: 0.09 ppm

Health Recommendations:

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

11 PM

24 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 1.04 µg/m³
PM₁₀: 1.29 µg/m³
O₃: 0.026 ppm
NO₂: 2 ppb
SO₂: 0 ppb
CO: 0.10 ppm

Health Recommendations:

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

Current Real-Time Air Quality Report

Weather Alerts and Warnings for Thornton

Severe Expected Likely

Red Flag Warning

Red Flag Warning issued March 18 at 12:29PM MDT until March 18 at 7:00PM MDT by NWS Denver CO

Mar 18, 12:29 PM → Mar 18, 7:00 PM

* AFFECTED AREA...Fire Weather Zones 239, 240, 243, 244, 245,
248, 249, 250 and 251.

* TIMING...Until 7 PM MDT this evening.

* WINDS...Northwest 10 to 20 mph with gusts around 30 mph.

* RELATIVE HUMIDITY...As low as 9 percent.

IMPACTS: Conditions will be favorable for rapid fire spread.
Avoid outdoor burning and any activity that may produce a
spark and start a wildfire.

+ Read More

A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior.

Updated: Mar 18, 5:15 PM Source: NWS Alert

Hourly Air Quality Forecast - AQI (US EPA)

Pollutant Concentrations:

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Weather Alerts and Warnings for Thornton

Red Flag Warning

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