Thunder Bay, 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
Thunder Bay, Ontario, Canada
AQI Trends: Highest and Lowest
Same Day Analysis (2nd July ):
On this day, AQI across the 5 years varied significantly: 2025 ranks 2nd highest AQI at 38 of Good air quality, showing improvement over 2023 on the same day.
Download 2024 Annual Data
World Air Quality Report

Day & Night AQI Trend: 2nd Jul - 3rd Jul 2025
Thunder Bay, Ontario, Canada
5 AM2nd Jul 2025
10 PM
4 AM3rd Jul 2025
47AQI
34AQI
38AQI
29AQI
In the last 24 hours,
Thunder Bay's AQI reached its highest point of 47 at 3 PM during the Day, while the lowest point, 29, was recorded at 4 AM during the Night between 2nd Jul and 3rd Jul 2025.
Day & Night AQI Trend : Jun - Jul 2025
Thunder Bay, Ontario, Canada
15°C11/17°C
17°C9/24°C
15°C9/21°C
15°C9/22°C
10°C4/16°C
9°C6/15°C
11°C8/15°C
16°C10/23°C
17°C9/23°C
11°C6/17°C
9°C4/13°C
9°C1/14°C
11°C3/17°C
14°C8/20°C
18°C9/25°C
18°C11/22°C
13°C11/16°C
11°C9/14°C
16°C8/28°C
14°C12/14°C
18°C10/27°C
18°C11/23°C
14°C6/20°C
15°C12/19°C
16°C10/22°C
16°C10/22°C
16°C10/22°C
20°C14/26°C
22°C15/29°C
22°C16/28°C
0°C0/0°C
38AQI
38AQI
39AQI
39AQI
2025 Days Vs Air Quality
Thunder Bay, Ontario, Canada
96%
176
4%
7
Total number of days with different AQI categories in last 184 days in 2025 (181 days remaining)
Under WHO’s Safe Air Quality Limits: 96%
Health Risk Level:
Very Low
In 2025, 96% of 184 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
Thunder Bay, Ontario, Canada
AQI levels in 2025
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
18AQI
22AQI
24AQI
26AQI
26AQI
24AQI
24AQI
24AQI
34AQI
41AQI
25AQI
23AQI
23AQI
25AQI
29AQI
26AQI
26AQI
26AQI
26AQI
24AQI
27AQI
27AQI
25AQI
28AQI
32AQI
28AQI
29AQI
24AQI
26AQI
27AQI
27AQI
25AQI
28AQI
27AQI
24AQI
23AQI
25AQI
26AQI
27AQI
29AQI
30AQI
36AQI
45AQI
28AQI
34AQI
26AQI
22AQI
22AQI
22AQI
27AQI
25AQI
28AQI
32AQI
34AQI
35AQI
25AQI
31AQI
24AQI
26AQI
29AQI
29AQI
37AQI
34AQI
28AQI
28AQI
27AQI
26AQI
30AQI
25AQI
29AQI
25AQI
25AQI
28AQI
63AQI
19AQI
23AQI
18AQI
25AQI
19AQI
21AQI
26AQI
26AQI
20AQI
24AQI
26AQI
18AQI
19AQI
16AQI
17AQI
17AQI
21AQI
18AQI
17AQI
22AQI
17AQI
18AQI
15AQI
16AQI
20AQI
29AQI
34AQI
36AQI
47AQI
29AQI
14AQI
16AQI
18AQI
23AQI
16AQI
20AQI
14AQI
18AQI
15AQI
15AQI
17AQI
17AQI
22AQI
25AQI
16AQI
15AQI
18AQI
17AQI
15AQI
16AQI
20AQI
26AQI
18AQI
17AQI
26AQI
20AQI
17AQI
26AQI
36AQI
33AQI
25AQI
24AQI
16AQI
17AQI
14AQI
14AQI
17AQI
14AQI
12AQI
15AQI
18AQI
19AQI
22AQI
23AQI
31AQI
29AQI
31AQI
29AQI
30AQI
49AQI
45AQI
55AQI
47AQI
59AQI
54AQI
59AQI
55AQI
61AQI
46AQI
30AQI
25AQI
28AQI
32AQI
30AQI
42AQI
36AQI
30AQI
33AQI
33AQI
33AQI
31AQI
38AQI
36AQI
27AQI
28AQI
26AQI
24AQI
31AQI
38AQI
26AQI
28AQI
26AQI
21AQI
21AQI
38AQI
35AQI
No. of days
202527AQI
Highest AQI recorded in
June38AQI
Lowest AQI recorded in
April21AQI
202430AQI
Highest AQI recorded in
September57AQI
Lowest AQI recorded in
November18AQI
202329AQI
Highest AQI recorded in
August38AQI
Lowest AQI recorded in
October20AQI
202227AQI
Highest AQI recorded in
February30AQI
Lowest AQI recorded in
September21AQI
202131AQI
Highest AQI recorded in
July47AQI
Lowest AQI recorded in
October20AQI
202027AQI
Highest AQI recorded in
March37AQI
Lowest AQI recorded in
August22AQI
Most & Least Polluted Years Over the Last 6 Years
Thunder Bay's annual 2025 AQI (27) shows an average percentage change of -6.7% (improved AQI) compared to previous years: 2020 (27), 2021 (31), 2022 (27), 2023 (29), 2024 (30).