Today | Weather | Monday, June 29, 2026
Active Weather Warnings

Weather in Thornton, Colorado

08:49 PM
Now
Cloudy Night
79° F
Feels Like 75°
Precipitation 0 %
Wind 9 mph
Humidity 13 %
Today
Night
Day 88°
Night 57°
Precipitation 3 %
Wind 7 mph

Thornton Weather Forecast Updated

57 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (June 29, 2025)
Sunny with a Chance of Thunderstorms

Day

84°

Night

57°

Wind

9 mph

UV Index

12

Precipitation

40 %

Air Quality in Thornton

NOW
109 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 30.18 µg/m³
PM10 32.37 µg/m³
O3 0.073 ppm
NO2 0.7 ppb
SO2 0.1 ppb
CO 0.18 ppm
NH3 2.29 µg/m³
NO 0 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:

Members of sensitive groups may experience health effects. The general public is not likely to be affected.

Show raw pollutant concentrations (µg/m³)
PM2.530.18 µg/m³
PM1032.37 µg/m³
O3142.94 µg/m³
NO21.24 µg/m³
SO20.36 µg/m³
CO208.99 µg/m³
NH32.29 µg/m³
NO0 µg/m³

Weather Alerts and Warnings for Thornton

Air Quality Alert

Air Quality Alert issued June 29 at 9:10AM MDT by NWS Denver CO
Jun 29, 9:10 AM Jun 30, 9:00 AM
The Colorado Department of Public Health and Environment has
issued the following...

WHAT...Action Day for Multiple Pollutants.

WHERE...Douglas, Jefferson, Denver, western Arapahoe, western
Adams, Broomfield, Boulder, Larimer, and Weld Counties

WHEN...400 PM Sunday June 28 to 400 PM Monday June 29

IMPACTS...Action Day for Multiple Pollutants is now in effect for
the Front Range Urban Corridor. Increasing wildfire smoke is
possible Sunday afternoon and evening, especially in and near
Denver and the local foothills to the west of the metro area.
Another plume of wildfire smoke could impact the entire northern
Front Range region Monday afternoon and evening. Both ozone and
fine particulates could reach the Unhealthy for Sensitive Groups
category or higher. For Colorado air quality conditions,
forecasts, and advisories, visit:
https://www.colorado.gov/airquality/colorado_summary.aspx If
possible, please help us reduce ozone pollution by limiting
driving gas and diesel-powered vehicles until at least 4 p.m.
Monday, June 29, 2026. Colorado is also addressing ozone pollution
through state policies. For more information about health impacts
and how ozone pollution forms in Colorado, visit:
https://cdphe.colorado.gov/ozone- pollution-and-your-health

HEALTH INFORMATION...People with heart or lung disease, older
adults, and children should reduce prolonged or heavy exertion.
During periods of heavier wildfire smoke, everyone should reduce
prolonged or heavy exertion.
Updated: Jun 29, 7:52 PM Source: NWS Alert