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HistoryAQIPM₂.₅PM₁₀COSO₂NO₂O₃

St Catharines, Ontario, Canada Historical Air Quality Analysis

Dive into detailed Air Quality Insights with historical data, monthly patterns, and yearly trends at your fingertips!

Good
050
Moderate
100
Poor
150
Unhealthy
200
Severe
300
Hazardous
301+

October Air Quality Analysis

St Catharines, Ontario, Canada

2022
2023
2024
2025
2026
AQI
.
Days

AQI Trends: Highest and Lowest

Highest AQI recorded on
4th Oct 2025
56AQI
Lowest AQI recorded on
23rd Oct 2025
13AQI

Same Day Analysis (2nd October):
On this day, AQI across the 5 years varied significantly: 2026 ranks 3rd highest AQI at 38 of Good air quality, showing improvement over 2025 and 2023 on the same day.

Day & Night AQI Trend: 1st Oct - 2nd Oct 2026

St Catharines, Ontario, Canada

AQI
Day
Night
.

6 AM1st Oct 2026

7 PM

5 AM2nd Oct 2026

Day time
Avg. Highest Time
11AM1st Oct

36AQI

Avg. Lowest Time
6PM1st Oct

21AQI

Night time
Avg. Highest Time
6AM1st Oct

46AQI

Avg. Lowest Time
7PM1st Oct

23AQI

In the last 24 hours,

St Catharines's AQI reached its highest point of 46 at 6 AM during the Night, while the lowest point, 21, was recorded at 6 PM during the Day between 1st Oct and 2nd Oct 2026.

Day & Night AQI Trend : Sep - Oct 2026

St Catharines, Ontario, Canada

SepOct
03rd - 04th04th - 05th05th - 06th06th - 07th07th - 08th08th - 09th09th - 10th10th - 11th11th - 12th12th - 13th13th - 14th14th - 15th15th - 16th16th - 17th17th - 18th18th - 19th19th - 20th20th - 21st21st - 22nd22nd - 23rd23rd - 24th24th - 25th25th - 26th26th - 27th27th - 28th28th - 29th29th - 30th30th - 01st01st - 02nd02nd
Day
Night
3rd Sep 2026406 AMAQI
3rd Sep 2026407 AMAQI
3rd Sep 2026508 AMAQI
3rd Sep 2026369 AMAQI
3rd Sep 20263410 AMAQI
3rd Sep 20263411 AMAQI
3rd Sep 20262512 PMAQI
3rd Sep 2026241 PMAQI
3rd Sep 2026282 PMAQI
3rd Sep 2026223 PMAQI
3rd Sep 2026244 PMAQI
3rd Sep 2026225 PMAQI
3rd Sep 2026266 PMAQI
3rd Sep 2026237 PMAQI
3rd Sep 2026248 PMAQI
3rd Sep 2026239 PMAQI
3rd Sep 20262410 PMAQI
3rd Sep 20262411 PMAQI
4th Sep 20262312 AMAQI
4th Sep 2026251 AMAQI
4th Sep 2026242 AMAQI
4th Sep 2026213 AMAQI
4th Sep 2026214 AMAQI
4th Sep 2026225 AMAQI

24°C20/28°C

4th Sep 2026226 AMAQI
4th Sep 2026217 AMAQI
4th Sep 2026268 AMAQI
4th Sep 2026299 AMAQI
4th Sep 20262810 AMAQI
4th Sep 20262611 AMAQI
4th Sep 20262912 PMAQI
4th Sep 2026301 PMAQI
4th Sep 2026382 PMAQI
4th Sep 2026543 PMAQI
4th Sep 2026334 PMAQI
4th Sep 2026265 PMAQI
4th Sep 2026256 PMAQI
4th Sep 2026257 PMAQI
4th Sep 2026288 PMAQI
4th Sep 2026279 PMAQI
4th Sep 20263210 PMAQI
4th Sep 20263011 PMAQI
5th Sep 20263612 AMAQI
5th Sep 2026311 AMAQI
5th Sep 2026312 AMAQI
5th Sep 2026383 AMAQI
5th Sep 2026624 AMAQI
5th Sep 2026655 AMAQI

22°C18/26°C

5th Sep 2026656 AMAQI
5th Sep 2026387 AMAQI
5th Sep 2026248 AMAQI
5th Sep 2026259 AMAQI
5th Sep 20262510 AMAQI
5th Sep 20262811 AMAQI
5th Sep 20262912 PMAQI
5th Sep 2026281 PMAQI
5th Sep 2026312 PMAQI
5th Sep 2026263 PMAQI
5th Sep 2026254 PMAQI
5th Sep 2026245 PMAQI
5th Sep 2026286 PMAQI
5th Sep 2026257 PMAQI
5th Sep 2026288 PMAQI
5th Sep 2026329 PMAQI
5th Sep 20265610 PMAQI
5th Sep 20264211 PMAQI
6th Sep 20262912 AMAQI
6th Sep 2026381 AMAQI
6th Sep 2026382 AMAQI
6th Sep 2026383 AMAQI
6th Sep 2026334 AMAQI
6th Sep 2026365 AMAQI

21°C16/27°C

6th Sep 2026366 AMAQI
6th Sep 2026367 AMAQI
6th Sep 2026288 AMAQI
6th Sep 2026299 AMAQI
6th Sep 20263010 AMAQI
6th Sep 20263411 AMAQI
6th Sep 20263212 PMAQI
6th Sep 2026341 PMAQI
6th Sep 2026382 PMAQI
6th Sep 2026313 PMAQI
6th Sep 2026264 PMAQI
6th Sep 2026385 PMAQI
6th Sep 2026456 PMAQI
6th Sep 2026267 PMAQI
6th Sep 2026248 PMAQI
6th Sep 2026309 PMAQI
6th Sep 20264610 PMAQI
6th Sep 20264211 PMAQI
7th Sep 20263812 AMAQI
7th Sep 2026421 AMAQI
7th Sep 2026232 AMAQI
7th Sep 2026423 AMAQI
7th Sep 2026404 AMAQI
7th Sep 2026215 AMAQI

20°C16/26°C

7th Sep 2026226 AMAQI
7th Sep 2026237 AMAQI
7th Sep 2026248 AMAQI
7th Sep 2026289 AMAQI
7th Sep 20262610 AMAQI
7th Sep 20262711 AMAQI
7th Sep 20262912 PMAQI
7th Sep 2026251 PMAQI
7th Sep 2026222 PMAQI
7th Sep 2026383 PMAQI
7th Sep 2026174 PMAQI
7th Sep 2026185 PMAQI
7th Sep 2026226 PMAQI
7th Sep 2026187 PMAQI
7th Sep 2026448 PMAQI
7th Sep 2026529 PMAQI
7th Sep 20264210 PMAQI
7th Sep 20264411 PMAQI
8th Sep 20264212 AMAQI
8th Sep 2026441 AMAQI
8th Sep 2026422 AMAQI
8th Sep 2026263 AMAQI
8th Sep 2026294 AMAQI
8th Sep 2026255 AMAQI

19°C12/27°C

8th Sep 2026266 AMAQI
8th Sep 2026367 AMAQI
8th Sep 2026298 AMAQI
8th Sep 2026289 AMAQI
8th Sep 20268510 AMAQI
8th Sep 20265211 AMAQI
8th Sep 20264512 PMAQI
8th Sep 2026311 PMAQI
8th Sep 2026462 PMAQI
8th Sep 2026423 PMAQI
8th Sep 2026264 PMAQI
8th Sep 2026265 PMAQI
8th Sep 2026226 PMAQI
8th Sep 2026257 PMAQI
8th Sep 2026318 PMAQI
8th Sep 2026269 PMAQI
8th Sep 20262110 PMAQI
8th Sep 20262511 PMAQI
9th Sep 20262912 AMAQI
9th Sep 2026251 AMAQI
9th Sep 2026252 AMAQI
9th Sep 2026233 AMAQI
9th Sep 2026254 AMAQI
9th Sep 2026245 AMAQI

20°C14/26°C

9th Sep 2026256 AMAQI
9th Sep 2026257 AMAQI
9th Sep 2026258 AMAQI
9th Sep 2026259 AMAQI
9th Sep 20262910 AMAQI
9th Sep 20263111 AMAQI
9th Sep 20263312 PMAQI
9th Sep 2026331 PMAQI
9th Sep 2026332 PMAQI
9th Sep 2026263 PMAQI
9th Sep 2026224 PMAQI
9th Sep 2026225 PMAQI
9th Sep 2026216 PMAQI
9th Sep 2026217 PMAQI
9th Sep 2026238 PMAQI
9th Sep 2026229 PMAQI
9th Sep 20262410 PMAQI
9th Sep 20262211 PMAQI
10th Sep 20262112 AMAQI
10th Sep 2026211 AMAQI
10th Sep 2026232 AMAQI
10th Sep 2026243 AMAQI
10th Sep 2026234 AMAQI
10th Sep 2026245 AMAQI

22°C18/26°C

10th Sep 2026216 AMAQI
10th Sep 2026217 AMAQI
10th Sep 2026328 AMAQI
10th Sep 2026429 AMAQI
10th Sep 20263310 AMAQI
10th Sep 20263311 AMAQI
10th Sep 20262912 PMAQI
10th Sep 2026301 PMAQI
10th Sep 2026272 PMAQI
10th Sep 2026323 PMAQI
10th Sep 2026254 PMAQI
10th Sep 2026235 PMAQI
10th Sep 2026466 PMAQI
10th Sep 2026347 PMAQI
10th Sep 2026248 PMAQI
10th Sep 2026259 PMAQI
10th Sep 20262710 PMAQI
10th Sep 20262611 PMAQI
11th Sep 20264712 AMAQI
11th Sep 2026641 AMAQI
11th Sep 2026342 AMAQI
11th Sep 2026413 AMAQI
11th Sep 2026504 AMAQI
11th Sep 2026625 AMAQI

22°C18/28°C

11th Sep 2026546 AMAQI
11th Sep 2026287 AMAQI
11th Sep 2026278 AMAQI
11th Sep 2026259 AMAQI
11th Sep 20262510 AMAQI
11th Sep 20262611 AMAQI
11th Sep 20262412 PMAQI
11th Sep 2026251 PMAQI
11th Sep 2026212 PMAQI
11th Sep 2026253 PMAQI
11th Sep 2026254 PMAQI
11th Sep 2026225 PMAQI
11th Sep 2026226 PMAQI
11th Sep 2026297 PMAQI
11th Sep 2026258 PMAQI
11th Sep 2026259 PMAQI
11th Sep 20262610 PMAQI
11th Sep 20264011 PMAQI
12th Sep 20263612 AMAQI
12th Sep 2026301 AMAQI
12th Sep 2026242 AMAQI
12th Sep 2026333 AMAQI
12th Sep 2026334 AMAQI
12th Sep 2026275 AMAQI

18°C13/24°C

12th Sep 2026246 AMAQI
12th Sep 2026227 AMAQI
12th Sep 2026238 AMAQI
12th Sep 2026219 AMAQI
12th Sep 20262610 AMAQI
12th Sep 20262711 AMAQI
12th Sep 20262712 PMAQI
12th Sep 2026271 PMAQI
12th Sep 2026382 PMAQI
12th Sep 2026223 PMAQI
12th Sep 2026255 PMAQI
12th Sep 2026256 PMAQI
12th Sep 2026387 PMAQI
12th Sep 2026388 PMAQI
12th Sep 2026669 PMAQI
12th Sep 20268710 PMAQI
12th Sep 20266811 PMAQI
13th Sep 20264712 AMAQI
13th Sep 2026331 AMAQI
13th Sep 2026462 AMAQI
13th Sep 2026383 AMAQI
13th Sep 2026384 AMAQI
13th Sep 2026385 AMAQI

20°C12/28°C

13th Sep 2026336 AMAQI
13th Sep 2026337 AMAQI
13th Sep 2026298 AMAQI
13th Sep 2026319 AMAQI
13th Sep 20263810 AMAQI
13th Sep 20264411 AMAQI
13th Sep 20263012 PMAQI
13th Sep 2026311 PMAQI
13th Sep 2026302 PMAQI
13th Sep 2026213 PMAQI
13th Sep 2026384 PMAQI
13th Sep 2026235 PMAQI
13th Sep 2026236 PMAQI
13th Sep 2026227 PMAQI
13th Sep 2026298 PMAQI
13th Sep 2026269 PMAQI
13th Sep 20262510 PMAQI
13th Sep 20262611 PMAQI
14th Sep 20262012 AMAQI
14th Sep 2026221 AMAQI
14th Sep 2026222 AMAQI
14th Sep 2026193 AMAQI
14th Sep 2026194 AMAQI
14th Sep 2026215 AMAQI

22°C18/24°C

14th Sep 2026206 AMAQI
14th Sep 2026167 AMAQI
14th Sep 2026538 AMAQI
14th Sep 2026259 AMAQI
14th Sep 20262410 AMAQI
14th Sep 20266011 AMAQI
14th Sep 20265612 PMAQI
14th Sep 2026341 PMAQI
14th Sep 2026502 PMAQI
14th Sep 2026383 PMAQI
14th Sep 2026254 PMAQI
14th Sep 2026245 PMAQI
14th Sep 2026226 PMAQI
14th Sep 2026487 PMAQI
14th Sep 2026308 PMAQI
14th Sep 2026329 PMAQI
14th Sep 20263310 PMAQI
14th Sep 20264011 PMAQI
15th Sep 20263312 AMAQI
15th Sep 2026281 AMAQI
15th Sep 2026292 AMAQI
15th Sep 2026293 AMAQI
15th Sep 2026274 AMAQI
15th Sep 2026315 AMAQI

17°C15/19°C

15th Sep 2026286 AMAQI
15th Sep 2026367 AMAQI
15th Sep 2026308 AMAQI
15th Sep 2026269 AMAQI
15th Sep 20263010 AMAQI
15th Sep 20262811 AMAQI
15th Sep 20262812 PMAQI
15th Sep 2026391 PMAQI
15th Sep 2026282 PMAQI
15th Sep 2026263 PMAQI
15th Sep 2026504 PMAQI
15th Sep 2026425 PMAQI
15th Sep 2026316 PMAQI
15th Sep 2026257 PMAQI
15th Sep 2026288 PMAQI
15th Sep 2026299 PMAQI
15th Sep 20262910 PMAQI
15th Sep 20264211 PMAQI
16th Sep 20264212 AMAQI
16th Sep 2026311 AMAQI
16th Sep 2026322 AMAQI
16th Sep 2026223 AMAQI
16th Sep 2026224 AMAQI
16th Sep 2026235 AMAQI

20°C15/24°C

16th Sep 2026256 AMAQI
16th Sep 2026297 AMAQI
16th Sep 2026278 AMAQI
16th Sep 2026309 AMAQI
16th Sep 20263410 AMAQI
16th Sep 20263811 AMAQI
16th Sep 20263312 PMAQI
16th Sep 2026331 PMAQI
16th Sep 2026462 PMAQI
16th Sep 2026503 PMAQI
16th Sep 2026504 PMAQI
16th Sep 2026475 PMAQI
16th Sep 2026476 PMAQI
16th Sep 2026527 PMAQI
16th Sep 2026528 PMAQI
16th Sep 2026389 PMAQI
16th Sep 20263810 PMAQI
16th Sep 20263311 PMAQI
17th Sep 20263112 AMAQI
17th Sep 2026291 AMAQI
17th Sep 2026422 AMAQI
17th Sep 2026423 AMAQI
17th Sep 2026494 AMAQI
17th Sep 2026295 AMAQI

21°C20/23°C

17th Sep 2026366 AMAQI
17th Sep 2026387 AMAQI
17th Sep 2026388 AMAQI
17th Sep 2026379 AMAQI
17th Sep 20264410 AMAQI
17th Sep 20263611 AMAQI
17th Sep 20263612 PMAQI
17th Sep 2026241 PMAQI
17th Sep 2026252 PMAQI
17th Sep 2026273 PMAQI
17th Sep 2026364 PMAQI
17th Sep 2026285 PMAQI
17th Sep 2026276 PMAQI
17th Sep 2026267 PMAQI
17th Sep 2026268 PMAQI
17th Sep 2026319 PMAQI
17th Sep 20263610 PMAQI
17th Sep 20263111 PMAQI
18th Sep 20262612 AMAQI
18th Sep 2026311 AMAQI
18th Sep 2026382 AMAQI
18th Sep 2026383 AMAQI
18th Sep 2026464 AMAQI
18th Sep 2026205 AMAQI

20°C18/21°C

18th Sep 2026226 AMAQI
18th Sep 2026247 AMAQI
18th Sep 2026258 AMAQI
18th Sep 2026249 AMAQI
18th Sep 20263610 AMAQI
18th Sep 20263811 AMAQI
18th Sep 20262912 PMAQI
18th Sep 2026271 PMAQI
18th Sep 2026422 PMAQI
18th Sep 2026293 PMAQI
18th Sep 2026254 PMAQI
18th Sep 2026265 PMAQI
18th Sep 2026296 PMAQI
18th Sep 2026267 PMAQI
18th Sep 2026268 PMAQI
18th Sep 2026269 PMAQI
18th Sep 20262810 PMAQI
18th Sep 20263811 PMAQI
19th Sep 20264012 AMAQI
19th Sep 2026461 AMAQI
19th Sep 2026282 AMAQI
19th Sep 2026223 AMAQI
19th Sep 2026264 AMAQI
19th Sep 2026245 AMAQI

18°C17/20°C

19th Sep 2026246 AMAQI
19th Sep 2026267 AMAQI
19th Sep 2026248 AMAQI
19th Sep 2026269 AMAQI
19th Sep 20262810 AMAQI
19th Sep 20262811 AMAQI
19th Sep 20262512 PMAQI
19th Sep 2026281 PMAQI
19th Sep 2026262 PMAQI
19th Sep 2026243 PMAQI
19th Sep 2026234 PMAQI
19th Sep 2026225 PMAQI
19th Sep 2026256 PMAQI
19th Sep 2026267 PMAQI
19th Sep 2026258 PMAQI
19th Sep 2026679 PMAQI
19th Sep 20264810 PMAQI
19th Sep 20263311 PMAQI
20th Sep 20263812 AMAQI
20th Sep 2026291 AMAQI
20th Sep 2026262 AMAQI
20th Sep 2026203 AMAQI
20th Sep 2026284 AMAQI
20th Sep 2026275 AMAQI

16°C14/18°C

20th Sep 2026286 AMAQI
20th Sep 2026287 AMAQI
20th Sep 2026368 AMAQI
20th Sep 2026319 AMAQI
20th Sep 20262810 AMAQI
20th Sep 20263611 AMAQI
20th Sep 20262312 PMAQI
20th Sep 2026281 PMAQI
20th Sep 2026272 PMAQI
20th Sep 2026283 PMAQI
20th Sep 2026284 PMAQI
20th Sep 2026255 PMAQI
20th Sep 2026246 PMAQI
20th Sep 2026277 PMAQI
20th Sep 2026298 PMAQI
20th Sep 2026319 PMAQI
20th Sep 20263010 PMAQI
20th Sep 20262811 PMAQI
21st Sep 20262812 AMAQI
21st Sep 2026261 AMAQI
21st Sep 2026272 AMAQI
21st Sep 2026263 AMAQI
21st Sep 2026294 AMAQI
21st Sep 2026265 AMAQI

17°C16/18°C

21st Sep 2026266 AMAQI
21st Sep 2026267 AMAQI
21st Sep 2026308 AMAQI
21st Sep 2026309 AMAQI
21st Sep 20262810 AMAQI
21st Sep 20263211 AMAQI
21st Sep 20262912 PMAQI
21st Sep 2026481 PMAQI
21st Sep 2026262 PMAQI
21st Sep 2026223 PMAQI
21st Sep 2026244 PMAQI
21st Sep 2026265 PMAQI
21st Sep 2026266 PMAQI
21st Sep 2026287 PMAQI
21st Sep 2026328 PMAQI
21st Sep 2026309 PMAQI
21st Sep 20262810 PMAQI
21st Sep 20262711 PMAQI
22nd Sep 20262912 AMAQI
22nd Sep 2026281 AMAQI
22nd Sep 2026262 AMAQI
22nd Sep 2026283 AMAQI
22nd Sep 2026264 AMAQI
22nd Sep 2026235 AMAQI

14°C13/17°C

22nd Sep 2026246 AMAQI
22nd Sep 2026287 AMAQI
22nd Sep 2026288 AMAQI
22nd Sep 2026289 AMAQI
22nd Sep 20262810 AMAQI
22nd Sep 20262911 AMAQI
22nd Sep 20262812 PMAQI
22nd Sep 2026281 PMAQI
22nd Sep 2026302 PMAQI
22nd Sep 2026283 PMAQI
22nd Sep 2026244 PMAQI
22nd Sep 2026245 PMAQI
22nd Sep 2026226 PMAQI
22nd Sep 2026227 PMAQI
22nd Sep 2026208 PMAQI
22nd Sep 2026269 PMAQI
22nd Sep 20263210 PMAQI
22nd Sep 20263411 PMAQI
23rd Sep 20262812 AMAQI
23rd Sep 2026261 AMAQI
23rd Sep 2026282 AMAQI
23rd Sep 2026243 AMAQI
23rd Sep 2026304 AMAQI
23rd Sep 2026285 AMAQI

15°C13/16°C

23rd Sep 2026296 AMAQI
23rd Sep 2026287 AMAQI
23rd Sep 2026318 AMAQI
23rd Sep 2026409 AMAQI
23rd Sep 20263810 AMAQI
23rd Sep 20263011 AMAQI
23rd Sep 20262812 PMAQI
23rd Sep 2026401 PMAQI
23rd Sep 2026262 PMAQI
23rd Sep 2026243 PMAQI
23rd Sep 2026244 PMAQI
23rd Sep 2026285 PMAQI
23rd Sep 2026246 PMAQI
23rd Sep 2026257 PMAQI
23rd Sep 2026248 PMAQI
23rd Sep 2026289 PMAQI
23rd Sep 20262810 PMAQI
23rd Sep 20263211 PMAQI
24th Sep 20263012 AMAQI
24th Sep 2026281 AMAQI
24th Sep 2026302 AMAQI
24th Sep 2026263 AMAQI
24th Sep 2026264 AMAQI
24th Sep 2026265 AMAQI

15°C12/18°C

24th Sep 2026246 AMAQI
24th Sep 2026247 AMAQI
24th Sep 2026288 AMAQI
24th Sep 2026319 AMAQI
24th Sep 20263010 AMAQI
24th Sep 20262611 AMAQI
24th Sep 20262612 PMAQI
24th Sep 2026261 PMAQI
24th Sep 2026232 PMAQI
24th Sep 2026213 PMAQI
24th Sep 2026204 PMAQI
24th Sep 2026205 PMAQI
24th Sep 2026246 PMAQI
24th Sep 2026227 PMAQI
24th Sep 2026228 PMAQI
24th Sep 2026249 PMAQI
24th Sep 20262410 PMAQI
24th Sep 20266211 PMAQI
25th Sep 20264612 AMAQI
25th Sep 2026361 AMAQI
25th Sep 2026322 AMAQI
25th Sep 2026403 AMAQI
25th Sep 2026384 AMAQI
25th Sep 2026215 AMAQI

15°C12/17°C

25th Sep 2026276 AMAQI
25th Sep 2026387 AMAQI
25th Sep 2026408 AMAQI
25th Sep 2026389 AMAQI
25th Sep 20262910 AMAQI
25th Sep 20262311 AMAQI
25th Sep 20262312 PMAQI
25th Sep 2026261 PMAQI
25th Sep 2026222 PMAQI
25th Sep 2026213 PMAQI
25th Sep 2026204 PMAQI
25th Sep 2026185 PMAQI
25th Sep 2026196 PMAQI
25th Sep 2026177 PMAQI
25th Sep 2026408 PMAQI
25th Sep 2026329 PMAQI
25th Sep 20262110 PMAQI
25th Sep 20262411 PMAQI
26th Sep 20262412 AMAQI
26th Sep 2026231 AMAQI
26th Sep 2026212 AMAQI
26th Sep 2026363 AMAQI
26th Sep 2026214 AMAQI
26th Sep 2026405 AMAQI

15°C13/18°C

26th Sep 2026386 AMAQI
26th Sep 2026477 AMAQI
26th Sep 2026478 AMAQI
26th Sep 2026449 AMAQI
26th Sep 20265610 AMAQI
26th Sep 20264211 AMAQI
26th Sep 20262312 PMAQI
26th Sep 2026251 PMAQI
26th Sep 2026272 PMAQI
26th Sep 2026443 PMAQI
26th Sep 2026294 PMAQI
26th Sep 2026255 PMAQI
26th Sep 2026236 PMAQI
26th Sep 2026217 PMAQI
26th Sep 2026258 PMAQI
26th Sep 2026369 PMAQI
26th Sep 20264510 PMAQI
26th Sep 20263811 PMAQI
27th Sep 20264412 AMAQI
27th Sep 2026511 AMAQI
27th Sep 2026462 AMAQI
27th Sep 2026423 AMAQI
27th Sep 2026324 AMAQI
27th Sep 2026255 AMAQI

17°C14/19°C

27th Sep 2026276 AMAQI
27th Sep 2026237 AMAQI
27th Sep 2026428 AMAQI
27th Sep 2026239 AMAQI
27th Sep 20262310 AMAQI
27th Sep 20262211 AMAQI
27th Sep 20263812 PMAQI
27th Sep 2026381 PMAQI
27th Sep 2026212 PMAQI
27th Sep 2026213 PMAQI
27th Sep 2026214 PMAQI
27th Sep 2026505 PMAQI
27th Sep 2026496 PMAQI
27th Sep 2026307 PMAQI
27th Sep 2026248 PMAQI
27th Sep 2026479 PMAQI
27th Sep 20264510 PMAQI
27th Sep 20262111 PMAQI
28th Sep 20262212 AMAQI
28th Sep 2026211 AMAQI
28th Sep 2026252 AMAQI
28th Sep 2026253 AMAQI
28th Sep 2026254 AMAQI
28th Sep 2026275 AMAQI

17°C15/20°C

28th Sep 2026296 AMAQI
28th Sep 2026387 AMAQI
28th Sep 2026318 AMAQI
28th Sep 2026279 AMAQI
28th Sep 20262510 AMAQI
28th Sep 20262511 AMAQI
28th Sep 20262912 PMAQI
28th Sep 2026271 PMAQI
28th Sep 2026382 PMAQI
28th Sep 2026343 PMAQI
28th Sep 2026224 PMAQI
28th Sep 2026245 PMAQI
28th Sep 2026236 PMAQI
28th Sep 2026257 PMAQI
28th Sep 2026258 PMAQI
28th Sep 2026259 PMAQI
28th Sep 20263110 PMAQI
28th Sep 20263811 PMAQI
29th Sep 20263312 AMAQI
29th Sep 2026331 AMAQI
29th Sep 2026382 AMAQI
29th Sep 2026333 AMAQI
29th Sep 2026464 AMAQI
29th Sep 2026385 AMAQI

16°C14/18°C

29th Sep 2026526 AMAQI
29th Sep 2026337 AMAQI
29th Sep 2026338 AMAQI
29th Sep 2026489 AMAQI
29th Sep 20264010 AMAQI
29th Sep 20263811 AMAQI
29th Sep 20265512 PMAQI
29th Sep 2026461 PMAQI
29th Sep 2026462 PMAQI
29th Sep 2026443 PMAQI
29th Sep 2026424 PMAQI
29th Sep 2026465 PMAQI
29th Sep 2026336 PMAQI
29th Sep 2026277 PMAQI
29th Sep 2026448 PMAQI
29th Sep 2026339 PMAQI
29th Sep 20265310 PMAQI
29th Sep 20264611 PMAQI
30th Sep 20264912 AMAQI
30th Sep 2026551 AMAQI
30th Sep 2026322 AMAQI
30th Sep 2026303 AMAQI
30th Sep 2026214 AMAQI
30th Sep 2026215 AMAQI

18°C16/19°C

30th Sep 2026216 AMAQI
30th Sep 2026217 AMAQI
30th Sep 2026228 AMAQI
30th Sep 2026229 AMAQI
30th Sep 20262210 AMAQI
30th Sep 20262111 AMAQI
30th Sep 20263012 PMAQI
30th Sep 2026211 PMAQI
30th Sep 2026322 PMAQI
30th Sep 2026213 PMAQI
30th Sep 2026214 PMAQI
30th Sep 2026305 PMAQI
30th Sep 2026326 PMAQI
30th Sep 2026217 PMAQI
30th Sep 2026308 PMAQI
30th Sep 2026219 PMAQI
30th Sep 20264210 PMAQI
30th Sep 20263811 PMAQI
1st Oct 20263312 AMAQI
1st Oct 2026251 AMAQI
1st Oct 2026252 AMAQI
1st Oct 2026293 AMAQI
1st Oct 2026314 AMAQI
1st Oct 2026405 AMAQI

19°C16/22°C

1st Oct 2026466 AMAQI
1st Oct 2026277 AMAQI
1st Oct 2026278 AMAQI
1st Oct 2026299 AMAQI
1st Oct 20263310 AMAQI
1st Oct 20263611 AMAQI
1st Oct 20263112 PMAQI
1st Oct 2026211 PMAQI
1st Oct 2026342 PMAQI
1st Oct 2026323 PMAQI
1st Oct 2026264 PMAQI
1st Oct 2026215 PMAQI
1st Oct 2026216 PMAQI
1st Oct 2026237 PMAQI
1st Oct 2026408 PMAQI
1st Oct 2026469 PMAQI
1st Oct 20264410 PMAQI
1st Oct 20264211 PMAQI
2nd Oct 20264212 AMAQI
2nd Oct 2026441 AMAQI
2nd Oct 2026442 AMAQI
2nd Oct 2026463 AMAQI
2nd Oct 2026404 AMAQI
2nd Oct 2026315 AMAQI

21°C18/25°C

2nd Oct 2026256 AMAQI
6 AM
2nd Oct 2026247 AMAQI
2nd Oct 2026258 AMAQI
2nd Oct 2026249 AMAQI
2nd Oct 20263410 AMAQI
2nd Oct 20264911 AMAQI
2nd Oct 20263812 PMAQI
12 PM
2nd Oct 2026541 PMAQI
2nd Oct 2026502 PMAQI
2nd Oct 2026523 PMAQI
2nd Oct 2026504 PMAQI
2nd Oct 2026485 PMAQI
2nd Oct 2026246 PMAQI
2nd Oct 2026237 PMAQI
7 PM
2nd Oct 2026228 PMAQI
2nd Oct 2026249 PMAQI
2nd Oct 20262410 PMAQI
2nd Oct 20262911 PMAQI
12 AM
5 AM

17°C13/20°C

Day time
Avg. Highest Time
10 AM - 11 AM

33AQI

2 hours / Day
60 hours / Month
Avg. Lowest Time
7 PM

27AQI

1 hours / Day
30 hours / Month
In the last 30 days, during the daytime, the highest AQI was between 10 AM to 11 AM (Avg. 33), while the lowest AQI was between 7 PM to 7 PM (Avg. 27).
Night time
Avg. Highest Time
10 PM - 11 PM

36AQI

2 hours / Day
60 hours / Month
Avg. Lowest Time
8 PM

29AQI

1 hours / Day
30 hours / Month
In the last 30 days, during the daytime, the highest AQI was between 10 PM to 11 PM (Avg. 36), while the lowest AQI was between 8 PM to 8 PM (Avg. 29).

2026 Days Vs Air Quality

St Catharines, Ontario, Canada

2026

94%

256

6%

16

Total number of days with different AQI categories in last 275 days in 2026 (90 days remaining)

Good
256 Days
Moderate
16 Days
Poor
0 Days
Unhealthy
0 Days
Severe
0 Days
Hazardous
0 Days

Under WHO’s Safe Air Quality Limits: 94%

Health Risk Level:

Very Low

In 2026, 94% of 275 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

St Catharines, Ontario, Canada

AQI levels in 2026

AQI (US)
PM₂.₅
PM₁₀
CO
SO₂
NO₂
O₃
Sun.Mon.Tue.Wed.Thu.Fri.Sat.

Jan.

Feb.

Mar.

Apr.

May

Jun.

Jul.

Aug.

Sep.

Oct.

Nov.

Dec.

-1th undefined 2026
-1th undefined 2026
-1th undefined 2026
-1th undefined 2026
1st January 2026
14AQI (US)
2nd January 2026
16AQI (US)
3rd January 2026
16AQI (US)
4th January 2026
24AQI (US)
5th January 2026
36AQI (US)
6th January 2026
71AQI (US)
7th January 2026
56AQI (US)
8th January 2026
49AQI (US)
9th January 2026
22AQI (US)
10th January 2026
16AQI (US)
11th January 2026
18AQI (US)
12th January 2026
20AQI (US)
13th January 2026
28AQI (US)
14th January 2026
31AQI (US)
15th January 2026
11AQI (US)
16th January 2026
17AQI (US)
17th January 2026
25AQI (US)
18th January 2026
22AQI (US)
19th January 2026
24AQI (US)
20th January 2026
18AQI (US)
21st January 2026
22AQI (US)
22nd January 2026
50AQI (US)
23rd January 2026
54AQI (US)
24th January 2026
47AQI (US)
25th January 2026
47AQI (US)
26th January 2026
47AQI (US)
27th January 2026
41AQI (US)
28th January 2026
46AQI (US)
29th January 2026
50AQI (US)
30th January 2026
55AQI (US)
31st January 2026
45AQI (US)
1st February 2026
45AQI (US)
2nd February 2026
54AQI (US)
3rd February 2026
50AQI (US)
4th February 2026
47AQI (US)
5th February 2026
49AQI (US)
6th February 2026
50AQI (US)
7th February 2026
40AQI (US)
8th February 2026
46AQI (US)
9th February 2026
45AQI (US)
10th February 2026
45AQI (US)
11th February 2026
40AQI (US)
12th February 2026
39AQI (US)
13th February 2026
47AQI (US)
14th February 2026
49AQI (US)
15th February 2026
45AQI (US)
16th February 2026
45AQI (US)
17th February 2026
60AQI (US)
18th February 2026
44AQI (US)
19th February 2026
41AQI (US)
20th February 2026
42AQI (US)
21st February 2026
37AQI (US)
22nd February 2026
37AQI (US)
23rd February 2026
38AQI (US)
24th February 2026
46AQI (US)
25th February 2026
44AQI (US)
26th February 2026
35AQI (US)
27th February 2026
37AQI (US)
28th February 2026
35AQI (US)
1st March 2026
38AQI (US)
2nd March 2026
62AQI (US)
3rd March 2026
48AQI (US)
4th March 2026
49AQI (US)
5th March 2026
42AQI (US)
6th March 2026
38AQI (US)
7th March 2026
37AQI (US)
8th March 2026
38AQI (US)
9th March 2026
37AQI (US)
10th March 2026
35AQI (US)
11th March 2026
41AQI (US)
12th March 2026
41AQI (US)
13th March 2026
40AQI (US)
14th March 2026
36AQI (US)
15th March 2026
33AQI (US)
16th March 2026
39AQI (US)
17th March 2026
34AQI (US)
18th March 2026
32AQI (US)
19th March 2026
39AQI (US)
20th March 2026
41AQI (US)
21st March 2026
38AQI (US)
22nd March 2026
38AQI (US)
23rd March 2026
41AQI (US)
24th March 2026
37AQI (US)
25th March 2026
36AQI (US)
26th March 2026
36AQI (US)
27th March 2026
28AQI (US)
28th March 2026
31AQI (US)
29th March 2026
30AQI (US)
30th March 2026
26AQI (US)
31st March 2026
28AQI (US)
1st April 2026
30AQI (US)
2nd April 2026
30AQI (US)
3rd April 2026
30AQI (US)
4th April 2026
32AQI (US)
5th April 2026
30AQI (US)
6th April 2026
31AQI (US)
7th April 2026
27AQI (US)
8th April 2026
34AQI (US)
9th April 2026
29AQI (US)
10th April 2026
31AQI (US)
11th April 2026
30AQI (US)
12th April 2026
30AQI (US)
13th April 2026
33AQI (US)
14th April 2026
38AQI (US)
15th April 2026
37AQI (US)
16th April 2026
32AQI (US)
17th April 2026
18th April 2026
30AQI (US)
19th April 2026
33AQI (US)
20th April 2026
28AQI (US)
21st April 2026
28AQI (US)
22nd April 2026
23rd April 2026
24AQI (US)
24th April 2026
25AQI (US)
25th April 2026
28AQI (US)
26th April 2026
33AQI (US)
27th April 2026
27AQI (US)
28th April 2026
26AQI (US)
29th April 2026
23AQI (US)
30th April 2026
26AQI (US)
1st May 2026
26AQI (US)
2nd May 2026
23AQI (US)
3rd May 2026
23AQI (US)
4th May 2026
35AQI (US)
5th May 2026
38AQI (US)
6th May 2026
31AQI (US)
7th May 2026
27AQI (US)
8th May 2026
29AQI (US)
9th May 2026
10th May 2026
30AQI (US)
11th May 2026
27AQI (US)
12th May 2026
26AQI (US)
13th May 2026
35AQI (US)
14th May 2026
22AQI (US)
15th May 2026
46AQI (US)
16th May 2026
52AQI (US)
17th May 2026
56AQI (US)
18th May 2026
57AQI (US)
19th May 2026
55AQI (US)
20th May 2026
52AQI (US)
21st May 2026
45AQI (US)
22nd May 2026
44AQI (US)
23rd May 2026
50AQI (US)
24th May 2026
47AQI (US)
25th May 2026
45AQI (US)
26th May 2026
34AQI (US)
27th May 2026
30AQI (US)
28th May 2026
28AQI (US)
29th May 2026
26AQI (US)
30th May 2026
28AQI (US)
31st May 2026
29AQI (US)
1st June 2026
31AQI (US)
2nd June 2026
32AQI (US)
3rd June 2026
32AQI (US)
4th June 2026
30AQI (US)
5th June 2026
32AQI (US)
6th June 2026
28AQI (US)
7th June 2026
25AQI (US)
8th June 2026
26AQI (US)
9th June 2026
30AQI (US)
10th June 2026
31AQI (US)
11th June 2026
30AQI (US)
12th June 2026
27AQI (US)
13th June 2026
26AQI (US)
14th June 2026
26AQI (US)
15th June 2026
26AQI (US)
16th June 2026
28AQI (US)
17th June 2026
28AQI (US)
18th June 2026
28AQI (US)
19th June 2026
26AQI (US)
20th June 2026
25AQI (US)
21st June 2026
23AQI (US)
22nd June 2026
26AQI (US)
23rd June 2026
25AQI (US)
24th June 2026
24AQI (US)
25th June 2026
26AQI (US)
26th June 2026
30AQI (US)
27th June 2026
33AQI (US)
28th June 2026
28AQI (US)
29th June 2026
26AQI (US)
30th June 2026
26AQI (US)
1st July 2026
34AQI (US)
2nd July 2026
42AQI (US)
3rd July 2026
30AQI (US)
4th July 2026
28AQI (US)
5th July 2026
29AQI (US)
6th July 2026
28AQI (US)
7th July 2026
33AQI (US)
8th July 2026
28AQI (US)
9th July 2026
30AQI (US)
10th July 2026
37AQI (US)
11th July 2026
32AQI (US)
12th July 2026
47AQI (US)
13th July 2026
39AQI (US)
14th July 2026
36AQI (US)
15th July 2026
44AQI (US)
16th July 2026
76AQI (US)
17th July 2026
90AQI (US)
18th July 2026
95AQI (US)
19th July 2026
48AQI (US)
20th July 2026
45AQI (US)
21st July 2026
54AQI (US)
22nd July 2026
28AQI (US)
23rd July 2026
34AQI (US)
24th July 2026
30AQI (US)
25th July 2026
28AQI (US)
26th July 2026
32AQI (US)
27th July 2026
43AQI (US)
28th July 2026
46AQI (US)
29th July 2026
24AQI (US)
30th July 2026
28AQI (US)
31st July 2026
34AQI (US)
1st August 2026
36AQI (US)
2nd August 2026
32AQI (US)
3rd August 2026
30AQI (US)
4th August 2026
26AQI (US)
5th August 2026
33AQI (US)
6th August 2026
37AQI (US)
7th August 2026
37AQI (US)
8th August 2026
34AQI (US)
9th August 2026
32AQI (US)
10th August 2026
34AQI (US)
11th August 2026
31AQI (US)
12th August 2026
32AQI (US)
13th August 2026
37AQI (US)
14th August 2026
34AQI (US)
15th August 2026
32AQI (US)
16th August 2026
28AQI (US)
17th August 2026
27AQI (US)
18th August 2026
33AQI (US)
19th August 2026
30AQI (US)
20th August 2026
33AQI (US)
21st August 2026
40AQI (US)
22nd August 2026
28AQI (US)
23rd August 2026
29AQI (US)
24th August 2026
36AQI (US)
25th August 2026
27AQI (US)
26th August 2026
42AQI (US)
27th August 2026
30AQI (US)
28th August 2026
26AQI (US)
29th August 2026
34AQI (US)
30th August 2026
32AQI (US)
31st August 2026
28AQI (US)
1st September 2026
42AQI (US)
2nd September 2026
36AQI (US)
3rd September 2026
32AQI (US)
4th September 2026
30AQI (US)
5th September 2026
35AQI (US)
6th September 2026
34AQI (US)
7th September 2026
32AQI (US)
8th September 2026
34AQI (US)
9th September 2026
28AQI (US)
10th September 2026
29AQI (US)
11th September 2026
33AQI (US)
12th September 2026
34AQI (US)
13th September 2026
36AQI (US)
14th September 2026
30AQI (US)
15th September 2026
31AQI (US)
16th September 2026
36AQI (US)
17th September 2026
35AQI (US)
18th September 2026
31AQI (US)
19th September 2026
30AQI (US)
20th September 2026
28AQI (US)
21st September 2026
28AQI (US)
22nd September 2026
27AQI (US)
23rd September 2026
28AQI (US)
24th September 2026
27AQI (US)
25th September 2026
30AQI (US)
26th September 2026
38AQI (US)
27th September 2026
38AQI (US)
28th September 2026
28AQI (US)
29th September 2026
43AQI (US)
30th September 2026
36AQI (US)
1st October 2026
36AQI (US)
2nd October 2026
38AQI (US)
3rd October 2026
4th October 2026
5th October 2026
6th October 2026
7th October 2026
8th October 2026
9th October 2026
10th October 2026
11th October 2026
12th October 2026
13th October 2026
14th October 2026
15th October 2026
16th October 2026
17th October 2026
18th October 2026
19th October 2026
20th October 2026
21st October 2026
22nd October 2026
23rd October 2026
24th October 2026
25th October 2026
26th October 2026
27th October 2026
28th October 2026
29th October 2026
30th October 2026
31st October 2026
1st November 2026
2nd November 2026
3rd November 2026
4th November 2026
5th November 2026
6th November 2026
7th November 2026
8th November 2026
9th November 2026
10th November 2026
11th November 2026
12th November 2026
13th November 2026
14th November 2026
15th November 2026
16th November 2026
17th November 2026
18th November 2026
19th November 2026
20th November 2026
21st November 2026
22nd November 2026
23rd November 2026
24th November 2026
25th November 2026
26th November 2026
27th November 2026
28th November 2026
29th November 2026
30th November 2026
1st December 2026
2nd December 2026
3rd December 2026
4th December 2026
5th December 2026
6th December 2026
7th December 2026
8th December 2026
9th December 2026
10th December 2026
11th December 2026
12th December 2026
13th December 2026
14th December 2026
15th December 2026
16th December 2026
17th December 2026
18th December 2026
19th December 2026
20th December 2026
21st December 2026
22nd December 2026
23rd December 2026
24th December 2026
25th December 2026
26th December 2026
27th December 2026
28th December 2026
29th December 2026
30th December 2026
31st December 2026

33AQI (US)

44AQI (US)

38AQI (US)

30AQI (US)

37AQI (US)

28AQI (US)

40AQI (US)

32AQI (US)

33AQI (US)

37AQI (US)

No. of days

Jan.Feb.Mar.Apr.MayJun.Jul.Aug.Sep.Oct.Nov.Dec.Total Days

202635AQI (US)

27
4
26
2
30
1
28
25
5
30
27
4
31
30
2
256
16

Highest AQI (US) recorded in

February

44AQI (US)

Lowest AQI (US) recorded in

June

28AQI (US)

202533AQI (US)

30
1
26
2
29
2
30
31
20
10
24
7
19
11
1
30
28
3
27
3
29
2
323
41
1

Highest AQI (US) recorded in

August

45AQI (US)

Lowest AQI (US) recorded in

May

21AQI (US)

202432AQI (US)

29
1
26
3
31
30
31
29
29
2
23
8
28
2
30
1
30
30
1
346
18

Highest AQI (US) recorded in

February

37AQI (US)

Lowest AQI (US) recorded in

November

23AQI (US)

202339AQI (US)

28
3
27
1
30
1
27
3
28
3
11
13
4
2
23
6
2
22
9
29
1
30
1
29
27
3
311
44
6
2

Highest AQI (US) recorded in

June

73AQI (US)

Lowest AQI (US) recorded in

October

26AQI (US)

202231AQI (US)

28
2
22
29
2
17
31
29
1
19
1
1
1
29
30
1
27
3
29
2
291
12
1

Highest AQI (US) recorded in

July

42AQI (US)

Lowest AQI (US) recorded in

August

20AQI (US)

202133AQI (US)

23
6
26
2
28
3
28
2
29
2
30
26
5
31
30
26
5
28
2
30
1
335
28

Highest AQI (US) recorded in

February

38AQI (US)

Lowest AQI (US) recorded in

September

24AQI (US)

202032AQI (US)

13
21
18
30
30
1
31
28
2
29
2
27
3
26
5
253
13

Highest AQI (US) recorded in

June

36AQI (US)

Lowest AQI (US) recorded in

October

28AQI (US)

Most & Least Polluted Years Over the Last 7 Years

Most Polluted Year Recorded
2023(Avg.)
39AQI (US)
Least Polluted Year Recorded
2022(Avg.)
31AQI (US)

St Catharines's annual 2026 AQI (US) (35) shows an average percentage change of 5.5% (worsened AQI (US)) compared to previous years: 2020 (32), 2021 (33), 2022 (31), 2023 (39), 2024 (32), 2025 (33).