Waterloo, Ontario, Canada 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
Waterloo, Ontario, Canada
AQI Trends: Highest and Lowest
Same Day Analysis (28th September):
On this day, AQI across the 5 years varied significantly: 2026 ranks 2nd highest AQI at 30 of Good air quality, showing improvement over 2023 on the same day.
Day & Night AQI Trend: 27th Sep - 28th Sep 2026
Waterloo, Ontario, Canada
7 AM27th Sep 2026
7 PM
6 AM28th Sep 2026
64AQI
34AQI
33AQI
20AQI
In the last 24 hours,
Waterloo's AQI reached its highest point of 64 at 8 AM during the Day, while the lowest point, 20, was recorded at 11 PM during the Night between 27th Sep and 28th Sep 2026.
Day & Night AQI Trend : Aug - Sep 2026
Waterloo, Ontario, Canada
19°C16/21°C
21°C18/24°C
25°C20/32°C
24°C20/32°C
22°C17/27°C
20°C16/25°C
19°C14/24°C
18°C13/24°C
18°C11/27°C
18°C11/26°C
20°C16/24°C
19°C14/25°C
17°C8/25°C
18°C10/26°C
18°C12/22°C
13°C9/18°C
17°C12/22°C
20°C16/23°C
18°C16/22°C
15°C12/20°C
13°C10/16°C
14°C10/19°C
10°C6/13°C
10°C6/15°C
12°C7/17°C
12°C9/17°C
13°C8/19°C
15°C9/21°C
16°C11/22°C
15°C11/20°C
35AQI
28AQI
33AQI
28AQI
2026 Days Vs Air Quality
Waterloo, Ontario, Canada
78%
209
20%
53
1%
3
0.3%
1
0.7%
2
Total number of days with different AQI categories in last 271 days in 2026 (94 days remaining)
Under WHO’s Safe Air Quality Limits: 78%
Health Risk Level:
Low
In 2026, 78% of 271 days were within WHO’s safe air quality limits. The risk of health issues is Low, but the long-term effects, especially on vulnerable individuals, remain uncertain.
Annual Air Quality Insights
Waterloo, Ontario, Canada
AQI levels in 2026
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
8AQI (US)
9AQI (US)
24AQI (US)
18AQI (US)
70AQI (US)
92AQI (US)
64AQI (US)
75AQI (US)
36AQI (US)
29AQI (US)
23AQI (US)
48AQI (US)
60AQI (US)
43AQI (US)
10AQI (US)
42AQI (US)
46AQI (US)
32AQI (US)
34AQI (US)
22AQI (US)
46AQI (US)
48AQI (US)
38AQI (US)
35AQI (US)
38AQI (US)
32AQI (US)
46AQI (US)
40AQI (US)
34AQI (US)
44AQI (US)
35AQI (US)
30AQI (US)
73AQI (US)
84AQI (US)
32AQI (US)
50AQI (US)
84AQI (US)
25AQI (US)
38AQI (US)
40AQI (US)
79AQI (US)
36AQI (US)
29AQI (US)
50AQI (US)
86AQI (US)
82AQI (US)
104AQI (US)
118AQI (US)
64AQI (US)
48AQI (US)
51AQI (US)
42AQI (US)
34AQI (US)
34AQI (US)
44AQI (US)
58AQI (US)
30AQI (US)
75AQI (US)
36AQI (US)
28AQI (US)
38AQI (US)
62AQI (US)
99AQI (US)
79AQI (US)
62AQI (US)
83AQI (US)
30AQI (US)
30AQI (US)
62AQI (US)
40AQI (US)
28AQI (US)
42AQI (US)
27AQI (US)
29AQI (US)
28AQI (US)
34AQI (US)
36AQI (US)
68AQI (US)
83AQI (US)
44AQI (US)
60AQI (US)
30AQI (US)
30AQI (US)
50AQI (US)
64AQI (US)
26AQI (US)
25AQI (US)
42AQI (US)
48AQI (US)
67AQI (US)
28AQI (US)
29AQI (US)
44AQI (US)
32AQI (US)
28AQI (US)
30AQI (US)
22AQI (US)
40AQI (US)
54AQI (US)
34AQI (US)
32AQI (US)
52AQI (US)
50AQI (US)
54AQI (US)
44AQI (US)
50AQI (US)
42AQI (US)
26AQI (US)
21AQI (US)
36AQI (US)
41AQI (US)
26AQI (US)
26AQI (US)
26AQI (US)
24AQI (US)
32AQI (US)
28AQI (US)
22AQI (US)
20AQI (US)
20AQI (US)
36AQI (US)
38AQI (US)
35AQI (US)
38AQI (US)
28AQI (US)
35AQI (US)
24AQI (US)
25AQI (US)
28AQI (US)
41AQI (US)
20AQI (US)
32AQI (US)
58AQI (US)
70AQI (US)
66AQI (US)
46AQI (US)
54AQI (US)
32AQI (US)
30AQI (US)
37AQI (US)
38AQI (US)
47AQI (US)
26AQI (US)
28AQI (US)
24AQI (US)
24AQI (US)
24AQI (US)
32AQI (US)
23AQI (US)
28AQI (US)
30AQI (US)
31AQI (US)
50AQI (US)
48AQI (US)
41AQI (US)
33AQI (US)
55AQI (US)
50AQI (US)
42AQI (US)
25AQI (US)
24AQI (US)
26AQI (US)
20AQI (US)
22AQI (US)
36AQI (US)
34AQI (US)
25AQI (US)
18AQI (US)
20AQI (US)
26AQI (US)
24AQI (US)
22AQI (US)
42AQI (US)
38AQI (US)
42AQI (US)
41AQI (US)
47AQI (US)
61AQI (US)
56AQI (US)
52AQI (US)
42AQI (US)
45AQI (US)
58AQI (US)
48AQI (US)
35AQI (US)
36AQI (US)
50AQI (US)
34AQI (US)
64AQI (US)
72AQI (US)
68AQI (US)
58AQI (US)
164AQI (US)
242AQI (US)
238AQI (US)
132AQI (US)
64AQI (US)
62AQI (US)
77AQI (US)
19AQI (US)
24AQI (US)
31AQI (US)
39AQI (US)
50AQI (US)
60AQI (US)
61AQI (US)
26AQI (US)
28AQI (US)
42AQI (US)
62AQI (US)
42AQI (US)
26AQI (US)
27AQI (US)
30AQI (US)
48AQI (US)
54AQI (US)
52AQI (US)
34AQI (US)
46AQI (US)
39AQI (US)
50AQI (US)
48AQI (US)
41AQI (US)
37AQI (US)
41AQI (US)
28AQI (US)
27AQI (US)
36AQI (US)
44AQI (US)
32AQI (US)
41AQI (US)
28AQI (US)
29AQI (US)
32AQI (US)
36AQI (US)
42AQI (US)
24AQI (US)
32AQI (US)
38AQI (US)
51AQI (US)
64AQI (US)
60AQI (US)
42AQI (US)
32AQI (US)
28AQI (US)
31AQI (US)
32AQI (US)
32AQI (US)
42AQI (US)
29AQI (US)
28AQI (US)
39AQI (US)
44AQI (US)
32AQI (US)
32AQI (US)
35AQI (US)
28AQI (US)
23AQI (US)
20AQI (US)
23AQI (US)
24AQI (US)
22AQI (US)
26AQI (US)
25AQI (US)
31AQI (US)
29AQI (US)
32AQI (US)
30AQI (US)
39AQI (US)
56AQI (US)
48AQI (US)
35AQI (US)
35AQI (US)
34AQI (US)
67AQI (US)
39AQI (US)
33AQI (US)
No. of days
202643AQI (US)
Highest AQI (US) recorded in
July67AQI (US)
Lowest AQI (US) recorded in
September33AQI (US)
202535AQI (US)
Highest AQI (US) recorded in
August48AQI (US)
Lowest AQI (US) recorded in
May24AQI (US)
202433AQI (US)
Highest AQI (US) recorded in
January37AQI (US)
Lowest AQI (US) recorded in
November25AQI (US)
202342AQI (US)
Highest AQI (US) recorded in
June72AQI (US)
Lowest AQI (US) recorded in
October30AQI (US)
202235AQI (US)
Highest AQI (US) recorded in
June39AQI (US)
Lowest AQI (US) recorded in
August17AQI (US)
202137AQI (US)
Highest AQI (US) recorded in
July46AQI (US)
Lowest AQI (US) recorded in
October30AQI (US)
202032AQI (US)
Highest AQI (US) recorded in
November35AQI (US)
Lowest AQI (US) recorded in
October24AQI (US)
Most & Least Polluted Years Over the Last 7 Years
Waterloo's annual 2026 AQI (US) (43) shows an average percentage change of 21.4% (worsened AQI (US)) compared to previous years: 2020 (32), 2021 (37), 2022 (35), 2023 (42), 2024 (33), 2025 (35).