Air quality index76Moderate

Acceptable for most people; unusually sensitive people should take it easier outdoors.

Next 24 hours

US AQI

81Now
76
71
7211 PM
73
75
742 AM
73
73
695 AM
65
61
608 AM
58
57
6011 AM
62
65
692 PM
73
77
745 PM
71
69

Air quality outlook

Worst hour each day

Today90Moderate
Fri 977Moderate
Sat 1051Moderate
Sun 11500Hazardous
Mon 1243Good

From our air-quality forecast models (GEOS-CF / GEFS aerosols). AQI uses the US EPA scale.

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About Longmont weather

Longmont is in Boulder County, Colorado, United States at 40.17°, -105.10°. Right now it’s 70° and partly cloudy; today’s high is 86° with a 1% chance of rain.

Colorado's climate is defined by dramatic elevation changes, from the eastern plains at around 3,500 feet to over 50 peaks exceeding 14,000 feet in the Rocky Mountains. Denver, known as the Mile High City, enjoys over 300 days of sunshine per year and has a semi-arid climate with low humidity. Temperature swings of 40 degrees or more in a single day are not uncommon along the Front Range.