20th Street, Boulder, Colorado, United States Historical Air Quality Analysis
Dive into detailed Air Quality Insights with historical data, monthly patterns, and yearly trends at your fingertips!
October Air Quality Analysis
20th Street, Boulder, Colorado, United States
AQI Trends: Highest and Lowest
Same Day Analysis (18th October ):
On this day, AQI across the 1 years varied significantly: 2025 ranks 1st highest AQI at 25 of Good air quality on the same day.
Download 2024 Annual Data
World Air Quality Report

Day & Night AQI Trend: 18th Oct - 19th Oct 2025
20th Street, Boulder, Colorado, United States
7 AM18th Oct 2025
6 PM
6 AM19th Oct 2025
58AQI
14AQI
59AQI
15AQI
In the last 24 hours,
20th Street's AQI reached its highest point of 59 at 2 AM during the Night, while the lowest point, undefined, was recorded at 6 AM during the Night between 18th Oct and 19th Oct 2025.
Day & Night AQI Trend : Sep - Oct 2025
20th Street, Boulder, Colorado, United States
17°C8/26°C
16°C11/25°C
19°C11/27°C
18°C13/23°C
9°C6/13°C
13°C5/22°C
17°C8/26°C
19°C12/28°C
19°C14/25°C
17°C12/23°C
15°C11/22°C
15°C8/23°C
19°C15/26°C
19°C12/26°C
21°C12/29°C
19°C12/26°C
11°C8/17°C
7°C4/9°C
10°C5/15°C
17°C10/26°C
16°C9/26°C
14°C11/18°C
15°C11/19°C
15°C10/21°C
9°C4/14°C
11°C3/19°C
14°C8/22°C
13°C7/21°C
12°C6/19°C
11°C6/16°C
--°C/°C
28AQI
19AQI
30AQI
18AQI
2025 Days Vs Air Quality
20th Street, Boulder, Colorado, United States
93%
193
7%
14
Total number of days with different AQI categories in last 292 days in 2025 (73 days remaining)
Under WHO’s Safe Air Quality Limits: 93%
Health Risk Level:
Very Low
In 2025, 93% of 292 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
20th Street, Boulder, Colorado, United States
AQI levels in 2025
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
19AQI
18AQI
22AQI
18AQI
22AQI
40AQI
23AQI
17AQI
17AQI
21AQI
24AQI
20AQI
27AQI
21AQI
42AQI
44AQI
37AQI
28AQI
24AQI
18AQI
32AQI
22AQI
20AQI
13AQI
25AQI
18AQI
15AQI
19AQI
26AQI
52AQI
24AQI
22AQI
25AQI
16AQI
16AQI
15AQI
15AQI
18AQI
19AQI
20AQI
19AQI
18AQI
18AQI
23AQI
20AQI
23AQI
24AQI
25AQI
27AQI
42AQI
15AQI
16AQI
17AQI
29AQI
14AQI
18AQI
18AQI
21AQI
30AQI
43AQI
17AQI
18AQI
28AQI
23AQI
18AQI
24AQI
26AQI
33AQI
23AQI
20AQI
34AQI
33AQI
25AQI
23AQI
33AQI
44AQI
36AQI
26AQI
25AQI
28AQI
38AQI
31AQI
28AQI
28AQI
26AQI
31AQI
35AQI
32AQI
34AQI
39AQI
47AQI
35AQI
27AQI
37AQI
37AQI
34AQI
30AQI
37AQI
31AQI
27AQI
25AQI
34AQI
29AQI
28AQI
31AQI
28AQI
32AQI
38AQI
60AQI
46AQI
30AQI
32AQI
43AQI
46AQI
53AQI
42AQI
33AQI
30AQI
29AQI
27AQI
35AQI
45AQI
47AQI
24AQI
27AQI
49AQI
39AQI
52AQI
50AQI
32AQI
23AQI
37AQI
54AQI
70AQI
52AQI
44AQI
44AQI
47AQI
36AQI
32AQI
50AQI
62AQI
58AQI
46AQI
29AQI
33AQI
22AQI
30AQI
42AQI
40AQI
41AQI
42AQI
42AQI
44AQI
29AQI
27AQI
38AQI
40AQI
36AQI
37AQI
43AQI
51AQI
69AQI
79AQI
70AQI
54AQI
38AQI
42AQI
23AQI
21AQI
17AQI
15AQI
16AQI
20AQI
21AQI
18AQI
19AQI
22AQI
26AQI
19AQI
15AQI
16AQI
26AQI
19AQI
19AQI
23AQI
23AQI
14AQI
15AQI
19AQI
24AQI
32AQI
22AQI
14AQI
18AQI
40AQI
46AQI
41AQI
25AQI
45AQI
29AQI
13AQI
26AQI
34AQI
26AQI
16AQI
25AQI
23AQI
24AQI
22AQI
32AQI
36AQI
41AQI
30AQI
28AQI
No. of days
202530AQI
Highest AQI recorded in
August41AQI
Lowest AQI recorded in
May22AQI
Most & Least Polluted Years Over the Last 1 Years
20th Street's annual 2025 AQI (30) shows an average percentage change of NaN% (improved AQI) compared to previous years: .