Today | Weather | Tuesday, June 30, 2026
Active Weather Warnings

Weather in Longmont, Colorado

01:19 PM
Now
Cloudy Weather
88° F
Feels Like 93°
Precipitation 8 %
Wind 10 mph
UV Index (0 - 11+) 11
Humidity 18 %
Today
Sunny with a Chance of Thunderstorms
Day 90°
Night 52°
Precipitation 55 %
Wind 8 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.

Longmont Weather Forecast Updated

Last updated on
Weather Forecast History
Last Year's Weather on This Day (June 30, 2025)
Stormy Weather

Day

79°

Night

59°

Wind

6 mph

UV Index

11

Precipitation

55 %

Air Quality in Longmont

NOW
41 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 4.5 µg/m³
PM10 6.19 µg/m³
O3 0.045 ppm
NO2 0.1 ppb
SO2 0.1 ppb
CO 0.06 ppm
NH3 0.42 µg/m³
NO 0.04 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)
PM2.54.5 µg/m³
PM106.19 µg/m³
O387.45 µg/m³
NO20.16 µg/m³
SO20.37 µg/m³
CO72.73 µg/m³
NH30.42 µg/m³
NO0.04 µg/m³

Weather Alerts and Warnings for Longmont

Air Quality Alert

Air Quality Alert issued June 29 at 10:10PM MDT by NWS Denver CO
Jun 29, 10:10 PM Jun 30, 4:00 PM
The Colorado Department of Public Health and Environment has
issued the following...

WHAT...Action Day Alert for Multiple Pollutants.

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

WHEN...400 PM Monday June 29 to 400 PM Tuesday June 30

IMPACTS...Ozone Action Day Alert is now in effect for the Front
Range Urban Corridor. Hot, sunny, and occasionally smoky weather
conditions will result in ozone concentrations occasionally
reaching the Unhealthy for Sensitive Groups category on Monday and
Tuesday. Particle pollution levels could also reach the Unhealthy
for Sensitive Groups category, or worse, due to the wildfire
smoke. 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, June 30, 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 30, 12:10 PM Source: NWS Alert