Air Quality in Longmont, United States

Clear
39.0°C · 6.8% humidity
39.0°
Feels 39.0°
38
Good
Air quality is satisfactory. Enjoy outdoor activities.
4 stations

Nearby Monitoring Stations

AQI Forecast Calibrated
16 2pm
16
16
38 5pm
32
27
24 8pm
22
20
19 11pm
18
18
17 2am
17
17
16 5am
16
18
18 8am
18
18
16 11am
15
15
Station readings
10
16
24
CAMS model adj -9
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
27
27
27
27
25
24
24
AD 728×90

Air Quality Index Trend

8h · 1 stn

Longmont's air quality is primarily affected by vehicle emissions and industrial activity. Seasonal wildfire smoke and weather patterns can cause periodic air quality deterioration.

6.8%
Humidity
21.5 km/h
Wind SSW
997.0 hPa
Pressure
6.9
UV High
GoodModerateUSGUnhealthyVery UnhealthyHazardous

Which pollutant is driving the AQI?

PM2.5▲
38
9.14 µg/m³
PM10
13
13.7 µg/m³
050100150200300500

What is the weather forecast for Longmont?

Temperature & Precipitation

PM2.5 Trend

8h · 1 station
PM2.59.14 µg/m³ ✓ WHO
Good
PM1013.7 µg/m³
Good
UV INDEX6.9
High
AD 300×250
Station readings (4 stations within 25 km)
9.14
Median
7.81
Average
4.87
Low
10.1
High
PM2.5 µg/m³ · Model: 5.9 · Bias: -3.2

What is the 7-day forecast for Longmont?

06-08
30.0° 16.0°
06-09
39.0° 19.2°
06-10
32.5° 13.1°
06-11
32.6° 14.1°
0.13 mm
06-12
36.2° 14.9°
1.44 mm
06-13
37.3° 15.2°
0.38 mm
06-14
30.6° 19.1°
0.06 mm
Both models agree Avg diff: 5.4°C

Where are air quality stations near Longmont?

33
Longmont Collocation 1
0.3 km PM2.5: 8.0 µg/m³
29
Longmont - Municipal, Colorado, USA
0.3 km PM2.5: 7.0 µg/m³
24
united-states-of-america-boulder-joslyn-court
20.4 km PM2.5: 5.8 µg/m³ PM10: 5.8 µg/m³
61
Athens, Boulder-CU, Colorado, USA
22.2 km PM2.5: 16.9 µg/m³
33
Platteville Middle School
24.1 km PM2.5: 8.0 µg/m³
37
Silver Creek
25.2 km PM2.5: 8.9 µg/m³
29
Anythink Brighton Library
31.3 km PM2.5: 6.9 µg/m³

What cities are near Longmont?

33 Erie 33 Louisville 21 Boulder 42 Loveland 35 Broomfield 32 Northglenn 27 Thornton 31 Sherrelwood 37 Arvada 33 Evans
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Data sources: AQI from ground-level monitoring stations via AQICN. Weather forecast from ECMWF (IFS & CAMS models). AQI calculated using US EPA standard. Updated 2026-06-08T23:12 UTC.