Boulder, Wyoming, United States Historical Air Quality Analysis
Dive into detailed Air Quality Insights with historical data, monthly patterns, and yearly trends at your fingertips!
September Air Quality Analysis
Boulder, Wyoming, United States
AQI Trends: Highest and Lowest
Same Day Analysis (4th September ):
On this day, AQI across the 1 years varied significantly: 2025 ranks 1st highest AQI at 63 of Moderate air quality on the same day.
Download 2024 Annual Data
World Air Quality Report

Day & Night AQI Trend: 4th Sep - 5th Sep 2025
Boulder, Wyoming, United States
6 AM4th Sep 2025
8 PM
5 AM5th Sep 2025
89AQI
54AQI
104AQI
66AQI
In the last 24 hours,
Boulder's AQI reached its highest point of 104 at 11 PM during the Night, while the lowest point, 54, was recorded at 7 AM during the Day between 4th Sep and 5th Sep 2025.
Day & Night AQI Trend : Aug - Sep 2025
Boulder, Wyoming, United States
20°C11/29°C
20°C11/29°C
15°C8/22°C
12°C4/21°C
13°C4/22°C
16°C7/24°C
18°C9/27°C
20°C11/30°C
19°C11/28°C
18°C11/28°C
15°C9/27°C
15°C10/25°C
18°C10/27°C
21°C12/30°C
22°C14/31°C
18°C13/24°C
19°C12/28°C
19°C9/27°C
16°C9/26°C
16°C11/24°C
17°C10/24°C
15°C12/19°C
14°C11/19°C
14°C6/21°C
15°C7/22°C
15°C6/23°C
17°C9/26°C
18°C9/26°C
18°C9/26°C
17°C9/26°C
--°C/°C
43AQI
40AQI
41AQI
39AQI
2025 Days Vs Air Quality
Boulder, Wyoming, United States
98%
160
2%
3
Total number of days with different AQI categories in last 248 days in 2025 (117 days remaining)
Under WHO’s Safe Air Quality Limits: 98%
Health Risk Level:
Very Low
In 2025, 98% of 248 days were within WHO’s safe air quality limits. The risk of health issues is Very Low, but health impacts are still unclear.
Annual Air Quality Insights
Boulder, Wyoming, United States
AQI levels in 2025
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
24AQI
18AQI
38AQI
34AQI
20AQI
22AQI
17AQI
16AQI
16AQI
17AQI
15AQI
15AQI
16AQI
15AQI
29AQI
29AQI
27AQI
18AQI
18AQI
16AQI
14AQI
16AQI
14AQI
12AQI
13AQI
13AQI
14AQI
18AQI
16AQI
18AQI
15AQI
15AQI
16AQI
13AQI
13AQI
13AQI
14AQI
16AQI
15AQI
18AQI
16AQI
13AQI
15AQI
15AQI
15AQI
17AQI
16AQI
18AQI
24AQI
17AQI
15AQI
15AQI
14AQI
15AQI
13AQI
15AQI
15AQI
16AQI
16AQI
15AQI
14AQI
16AQI
17AQI
17AQI
15AQI
19AQI
19AQI
19AQI
16AQI
15AQI
16AQI
17AQI
18AQI
20AQI
21AQI
25AQI
23AQI
20AQI
20AQI
21AQI
22AQI
21AQI
21AQI
19AQI
21AQI
20AQI
29AQI
37AQI
32AQI
24AQI
24AQI
27AQI
23AQI
32AQI
29AQI
22AQI
20AQI
23AQI
23AQI
23AQI
23AQI
26AQI
26AQI
25AQI
24AQI
25AQI
24AQI
35AQI
30AQI
29AQI
25AQI
22AQI
26AQI
32AQI
39AQI
26AQI
21AQI
23AQI
21AQI
18AQI
24AQI
27AQI
30AQI
32AQI
26AQI
33AQI
33AQI
37AQI
29AQI
21AQI
19AQI
33AQI
50AQI
44AQI
35AQI
25AQI
18AQI
22AQI
31AQI
28AQI
33AQI
34AQI
30AQI
23AQI
17AQI
17AQI
17AQI
20AQI
25AQI
27AQI
36AQI
44AQI
52AQI
56AQI
26AQI
20AQI
36AQI
38AQI
28AQI
35AQI
34AQI
38AQI
63AQI
26AQI
17AQI
16AQI
22AQI
27AQI
30AQI
43AQI
No. of days
202523AQI
Highest AQI recorded in
September43AQI
Lowest AQI recorded in
May16AQI
Most & Least Polluted Years Over the Last 1 Years
Boulder's annual 2025 AQI (23) shows an average percentage change of NaN% (improved AQI) compared to previous years: .