Fort Collins, Colorado, United States Historical Air Quality Analysis
Dive into detailed Air Quality Insights with historical data, monthly patterns, and yearly trends at your fingertips!
August Air Quality Analysis
Fort Collins, Colorado, United States
AQI Trends: Highest and Lowest
Same Day Analysis (21st August ):
On this day, AQI across the 5 years varied significantly: 2025 ranks 1st highest AQI at 44 of Good air quality on the same day.
Download 2024 Annual Data
World Air Quality Report

Day & Night AQI Trend: 21st Aug - 22nd Aug 2025
Fort Collins, Colorado, United States
6 AM21st Aug 2025
8 PM
5 AM22nd Aug 2025
51AQI
41AQI
50AQI
28AQI
In the last 24 hours,
Fort Collins's AQI reached its highest point of 51 at 10 AM during the Day, while the lowest point, 28, was recorded at 4 AM during the Night between 21st Aug and 22nd Aug 2025.
Day & Night AQI Trend : Jul - Aug 2025
Fort Collins, Colorado, United States
23°C16/31°C
20°C15/30°C
23°C15/34°C
25°C15/36°C
26°C15/36°C
27°C16/38°C
24°C20/31°C
21°C18/27°C
21°C15/29°C
21°C13/31°C
21°C13/31°C
23°C13/32°C
24°C14/34°C
26°C13/38°C
26°C15/38°C
27°C16/37°C
26°C17/37°C
24°C16/31°C
20°C16/25°C
21°C12/30°C
23°C16/32°C
26°C14/38°C
26°C16/38°C
25°C15/34°C
24°C17/32°C
25°C17/33°C
25°C18/35°C
25°C15/34°C
26°C15/37°C
27°C16/38°C
--°C/°C
45AQI
40AQI
41AQI
39AQI
2025 Days Vs Air Quality
Fort Collins, Colorado, United States
96%
224
4%
9
Total number of days with different AQI categories in last 234 days in 2025 (131 days remaining)
Under WHO’s Safe Air Quality Limits: 96%
Health Risk Level:
Very Low
In 2025, 96% of 234 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
Fort Collins, Colorado, United States
AQI levels in 2025
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
38AQI
33AQI
48AQI
33AQI
25AQI
40AQI
37AQI
46AQI
24AQI
25AQI
25AQI
21AQI
21AQI
23AQI
29AQI
39AQI
38AQI
19AQI
31AQI
23AQI
37AQI
19AQI
24AQI
26AQI
19AQI
38AQI
54AQI
47AQI
42AQI
32AQI
33AQI
22AQI
20AQI
26AQI
48AQI
44AQI
24AQI
27AQI
27AQI
22AQI
21AQI
40AQI
31AQI
40AQI
46AQI
41AQI
37AQI
35AQI
37AQI
29AQI
38AQI
26AQI
27AQI
21AQI
16AQI
13AQI
16AQI
18AQI
21AQI
23AQI
25AQI
27AQI
18AQI
16AQI
17AQI
15AQI
19AQI
16AQI
22AQI
20AQI
22AQI
23AQI
22AQI
16AQI
15AQI
19AQI
17AQI
15AQI
22AQI
14AQI
16AQI
14AQI
16AQI
19AQI
38AQI
35AQI
34AQI
22AQI
23AQI
42AQI
20AQI
17AQI
18AQI
22AQI
30AQI
28AQI
34AQI
29AQI
45AQI
47AQI
48AQI
39AQI
26AQI
23AQI
36AQI
33AQI
23AQI
14AQI
27AQI
30AQI
17AQI
25AQI
33AQI
53AQI
19AQI
24AQI
39AQI
17AQI
18AQI
19AQI
15AQI
18AQI
23AQI
24AQI
24AQI
21AQI
24AQI
36AQI
32AQI
30AQI
27AQI
24AQI
32AQI
34AQI
15AQI
15AQI
19AQI
32AQI
13AQI
15AQI
16AQI
22AQI
31AQI
39AQI
17AQI
21AQI
34AQI
21AQI
21AQI
26AQI
25AQI
28AQI
19AQI
20AQI
38AQI
41AQI
25AQI
21AQI
32AQI
43AQI
39AQI
29AQI
29AQI
32AQI
33AQI
28AQI
29AQI
27AQI
26AQI
32AQI
32AQI
37AQI
36AQI
37AQI
49AQI
37AQI
30AQI
33AQI
37AQI
34AQI
29AQI
32AQI
31AQI
28AQI
25AQI
35AQI
28AQI
31AQI
31AQI
32AQI
31AQI
37AQI
56AQI
44AQI
37AQI
32AQI
43AQI
50AQI
49AQI
43AQI
33AQI
33AQI
31AQI
27AQI
29AQI
33AQI
40AQI
31AQI
32AQI
48AQI
43AQI
52AQI
49AQI
36AQI
26AQI
38AQI
56AQI
83AQI
61AQI
54AQI
45AQI
37AQI
39AQI
39AQI
43AQI
46AQI
50AQI
52AQI
29AQI
33AQI
23AQI
36AQI
44AQI
32AQI
29AQI
21AQI
28AQI
24AQI
32AQI
36AQI
44AQI
No. of days
202530AQI
Highest AQI recorded in
August44AQI
Lowest AQI recorded in
March21AQI
202427AQI
Highest AQI recorded in
October41AQI
Lowest AQI recorded in
May15AQI
202326AQI
Highest AQI recorded in
January40AQI
Lowest AQI recorded in
April18AQI
202228AQI
Highest AQI recorded in
August38AQI
Lowest AQI recorded in
July20AQI
202135AQI
Highest AQI recorded in
August59AQI
Lowest AQI recorded in
May24AQI
202039AQI
Highest AQI recorded in
September63AQI
Lowest AQI recorded in
June20AQI
Most & Least Polluted Years Over the Last 6 Years
Fort Collins's annual 2025 AQI (30) shows an average percentage change of 1.1% (worsened AQI) compared to previous years: 2020 (39), 2021 (35), 2022 (28), 2023 (26), 2024 (27).