St Thomas, Ontario, Canada Historical Air Quality Analysis
Dive into detailed Air Quality Insights with historical data, monthly patterns, and yearly trends at your fingertips!
July Air Quality Analysis
St Thomas, Ontario, Canada
AQI Trends: Highest and Lowest
Same Day Analysis (31st July ):
On this day, AQI across the 5 years varied significantly: 2025 ranks 2nd highest AQI at 89 of Moderate air quality, showing improvement over 2021 on the same day.
Download 2024 Annual Data
World Air Quality Report
2025 Days Vs Air Quality
St Thomas, Ontario, Canada
88%
187
12%
25
Total number of days with different AQI categories in last 213 days in 2025 (152 days remaining)
Under WHO’s Safe Air Quality Limits: 88%
Health Risk Level:
Low
In 2025, 88% of 213 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
St Thomas, Ontario, Canada
AQI levels in 2025
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
21AQI
22AQI
26AQI
26AQI
24AQI
22AQI
24AQI
27AQI
26AQI
45AQI
63AQI
46AQI
32AQI
28AQI
25AQI
49AQI
46AQI
28AQI
27AQI
26AQI
24AQI
27AQI
37AQI
27AQI
47AQI
31AQI
26AQI
29AQI
27AQI
27AQI
42AQI
28AQI
28AQI
53AQI
26AQI
25AQI
29AQI
28AQI
36AQI
35AQI
31AQI
48AQI
34AQI
28AQI
37AQI
40AQI
30AQI
28AQI
27AQI
24AQI
24AQI
29AQI
53AQI
55AQI
51AQI
50AQI
49AQI
49AQI
27AQI
30AQI
29AQI
32AQI
34AQI
31AQI
28AQI
31AQI
32AQI
30AQI
29AQI
32AQI
28AQI
25AQI
47AQI
55AQI
23AQI
15AQI
24AQI
30AQI
23AQI
16AQI
16AQI
17AQI
20AQI
18AQI
18AQI
29AQI
35AQI
51AQI
29AQI
19AQI
16AQI
18AQI
22AQI
17AQI
18AQI
17AQI
17AQI
15AQI
18AQI
25AQI
33AQI
30AQI
28AQI
28AQI
16AQI
14AQI
19AQI
33AQI
42AQI
20AQI
26AQI
15AQI
23AQI
38AQI
45AQI
23AQI
17AQI
25AQI
37AQI
20AQI
28AQI
34AQI
20AQI
20AQI
22AQI
21AQI
27AQI
21AQI
25AQI
25AQI
20AQI
26AQI
24AQI
17AQI
24AQI
29AQI
24AQI
22AQI
16AQI
16AQI
16AQI
16AQI
12AQI
11AQI
15AQI
20AQI
23AQI
16AQI
25AQI
36AQI
27AQI
19AQI
21AQI
35AQI
67AQI
57AQI
68AQI
71AQI
88AQI
66AQI
54AQI
60AQI
70AQI
52AQI
38AQI
40AQI
38AQI
32AQI
34AQI
27AQI
32AQI
40AQI
43AQI
54AQI
56AQI
50AQI
49AQI
43AQI
34AQI
30AQI
33AQI
30AQI
36AQI
44AQI
44AQI
51AQI
52AQI
49AQI
39AQI
53AQI
49AQI
50AQI
44AQI
40AQI
50AQI
69AQI
75AQI
47AQI
25AQI
24AQI
24AQI
40AQI
26AQI
23AQI
34AQI
36AQI
46AQI
35AQI
39AQI
42AQI
46AQI
89AQI
32AQI
36AQI
28AQI
24AQI
22AQI
47AQI
44AQI
No. of days
202533AQI
Highest AQI recorded in
June47AQI
Lowest AQI recorded in
May22AQI
202433AQI
Highest AQI recorded in
January37AQI
Lowest AQI recorded in
November26AQI
202341AQI
Highest AQI recorded in
June73AQI
Lowest AQI recorded in
October30AQI
202233AQI
Highest AQI recorded in
June37AQI
Lowest AQI recorded in
August21AQI
202136AQI
Highest AQI recorded in
July48AQI
Lowest AQI recorded in
November27AQI
202033AQI
Highest AQI recorded in
July37AQI
Lowest AQI recorded in
October28AQI
Most & Least Polluted Years Over the Last 6 Years
St Thomas's annual 2025 AQI (33) shows an average percentage change of -5.1% (improved AQI) compared to previous years: 2020 (33), 2021 (36), 2022 (33), 2023 (41), 2024 (33).
