Air Quality in Longmont, United States

Drizzle
16.2°C · 37.4% humidity
16.2°
Feels 16.2°
17
Good
Air quality is satisfactory. Enjoy outdoor activities.
2 stations

Nearby Monitoring Stations

AQI Forecast Calibrated
23 7pm
20
77
77 10pm
90
90
102 1am
102
115
115 4am
115
115
115 7am
102
102
90 10am
90
90
90 1pm
90
90
90 4pm
90
90
Station readings
23
20
CAMS model adj +65
12
12
12
12
25
25
37
37
50
50
50
50
50
37
37
25
25
25
25
25
25
25
25
25
AD 728×90

PM2.5 Trend (24h)

25h · 29 stations
37.4%
Humidity
49.8 km/h
Wind NW
1006.8 hPa
Pressure
1.4
UV Low
GoodModerateUSGUnhealthyVery UnhealthyHazardous

What is the weather forecast for Longmont?

Temperature & Precipitation

PM2.54.06 µg/m³ ✓ WHO
Good
PM1013.7 µg/m³
Good
UV INDEX1.4
Low
AD 300×250
Station readings (2 stations within 25 km)
4.06
Median
4.06
Average
3.0
Low
5.12
High
PM2.5 µg/m³ · Model: 4.4 · Bias: +0.3

What is the 7-day forecast for Longmont?

04-09
17.9° 8.2°
1.63 mm
04-10
16.2° 8.9°
7.19 mm
04-11
17.5° 8.2°
5.0 mm
04-12
18.3° 7.3°
0.88 mm
04-13
15.8° 5.1°
0.31 mm
04-14
11.3° 1.1°
10.94 mm
04-15
12.5° 3.2°
0.13 mm
Both models agree Avg diff: 3.7°C

Where are air quality stations near Longmont?

22
Longmont Collocation 1
0.3 km PM2.5: 5.2 µg/m³
–
united-states-of-america-boulder-joslyn-court
20.4 km PM2.5: 0.0 µg/m³ PM10: 0.0 µg/m³
73
Athens, Boulder-CU, Colorado, USA
22.2 km
12
Platteville Middle School
24.1 km PM2.5: 3.0 µg/m³
24
Silver Creek
25.2 km PM2.5: 5.8 µg/m³
20
Anythink Brighton Library
31.3 km PM2.5: 4.8 µg/m³

What cities are near Longmont?

21 Erie 21 Louisville 21 Boulder 22 Loveland 22 Broomfield 21 Northglenn 21 Thornton 21 Sherrelwood 22 Arvada 12 Evans

Data sources: AQI from ground-level monitoring stations via AQICN. Weather forecast from ECMWF (IFS & CAMS models). AQI calculated using US EPA standard. Updated 2026-04-09T22:11 UTC.