Today | Weather | Tuesday, July 21, 2026
Active Weather Warnings

Weather in Westminster, Colorado

02:05 AM
Now
Cloudy Night
75° F
Feels Like 72°
Precipitation 0 %
Wind 8 mph
Humidity 48 %
Today
Sunny with a Chance of Thunderstorms
Day 95°
Night 66°
Precipitation 55 %
Wind 12 mph
UV Index (0 - 11+) 11

Warning: Extreme UV Index Today: 11

Overexposure to the sun's harmful UV rays can cause sunburn and increase the risk of developing skin cancer, including melanoma. Protect yourself by wearing clothing that covers your skin, sunglasses, and a hat. Apply a broad-spectrum sunscreen with an SPF of 30 or higher every two hours, even on cloudy days. Minimize direct sun exposure during peak hours (10 AM to 4 PM) to reduce the risk.

Westminster Weather Forecast Updated

Last updated on
Weather Forecast History
Last Year's Weather on This Day (July 21, 2025)
Cloudy Night

Day

91°

Night

64°

Wind

6 mph

Precipitation

1 %

Air Quality in Westminster

NOW
24 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 2.82 µg/m³
PM10 3.13 µg/m³
O3 0.026 ppm
NO2 1.9 ppb
SO2 0 ppb
CO 0.08 ppm
NH3 1.78 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:

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

Show raw pollutant concentrations (µg/m³)
PM2.52.82 µg/m³
PM103.13 µg/m³
O350.57 µg/m³
NO23.61 µg/m³
SO20.11 µg/m³
CO93.23 µg/m³
NH31.78 µg/m³
NO0 µg/m³

Weather Alerts and Warnings for Westminster

Air Quality Alert

Air Quality Alert issued July 20 at 4:10PM MDT by NWS Denver CO
Jul 20, 4:10 PM Jul 21, 4:00 PM
The Colorado Department of Public Health and Environment has
issued the following...

WHAT...Ozone Action Day Alert.

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

WHEN...400 PM Monday July 20 to 400 PM Tuesday July 21

IMPACTS...Ozone Action Day Alert is now in effect for the Front
Range Urban Corridor. Hot and stagnant weather conditions will
result in ozone concentrations reaching the Unhealthy for
Sensitive Groups category both Monday and Tuesday during the
afternoon and evening hours. 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.
Tuesday, July 21, 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...Increasing likelihood of respiratory symptoms
and breathing discomfort in active children and adults and people
with lung disease, such as asthma. Active children and adults, and
people with lung disease, such as asthma, should reduce prolonged
or heavy outdoor exertion.
Updated: Jul 21, 12:44 AM Source: NWS Alert