Country Background
HistoryAQIPM2.5PM10COSO2NO2O3

Boulder, Colorado, United States 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+

July Air Quality Analysis

Boulder, Colorado, United States

2021
2022
2023
2024
2025
AQI
.
Days

AQI Trends: Highest and Lowest

Highest AQI recorded on
31st Jul 2024
73AQI
Lowest AQI recorded on
24th Jul 2022
14AQI

Same Day Analysis (29th July ):
On this day, AQI across the 5 years varied significantly: 2025 ranks 2nd highest AQI at 48 of Good air quality, showing improvement over 2021 on the same day.

Download 2024 Annual Data

World Air Quality Report

Globe

Day & Night AQI Trend: 30th Jul - 31st Jul 2025

Boulder, Colorado, United States

AQI
Day
Night
.

5 AM30th Jul 2025

8 PM

4 AM31st Jul 2025

Day time
Avg. Highest Time
2PM30th Jul

39AQI

Avg. Lowest Time
6AM30th Jul

32AQI

Night time
Avg. Highest Time
11PM30th Jul

45AQI

Avg. Lowest Time
9PM30th Jul

42AQI

In the last 24 hours,

Boulder's AQI reached its highest point of 45 at 11 PM during the Night, while the lowest point, undefined, was recorded at 4 AM during the Night between 30th Jul and 31st Jul 2025.

Day & Night AQI Trend : Jul 2025

Boulder, Colorado, United States

Jul
01st - 02nd02nd - 03rd03rd - 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 - 31st31st
Day
Night
1st Jul 2025325 AMAQI
1st Jul 2025316 AMAQI
1st Jul 2025337 AMAQI
1st Jul 2025338 AMAQI
1st Jul 2025349 AMAQI
1st Jul 20253310 AMAQI
1st Jul 20253211 AMAQI
1st Jul 20253212 PMAQI
1st Jul 2025311 PMAQI
1st Jul 2025332 PMAQI
1st Jul 2025323 PMAQI
1st Jul 2025324 PMAQI
1st Jul 2025315 PMAQI
1st Jul 2025296 PMAQI
1st Jul 2025317 PMAQI
1st Jul 2025338 PMAQI
1st Jul 2025329 PMAQI
1st Jul 20253010 PMAQI
1st Jul 20253011 PMAQI
2nd Jul 20252812 AMAQI
2nd Jul 2025281 AMAQI
2nd Jul 2025282 AMAQI
2nd Jul 2025293 AMAQI
2nd Jul 2025294 AMAQI

22°C13/33°C

2nd Jul 2025245 AMAQI
2nd Jul 2025236 AMAQI
2nd Jul 2025237 AMAQI
2nd Jul 2025238 AMAQI
2nd Jul 2025239 AMAQI
2nd Jul 20252310 AMAQI
2nd Jul 20252311 AMAQI
2nd Jul 20253012 PMAQI
2nd Jul 2025321 PMAQI
2nd Jul 2025322 PMAQI
2nd Jul 2025323 PMAQI
2nd Jul 2025324 PMAQI
2nd Jul 2025325 PMAQI
2nd Jul 2025326 PMAQI
2nd Jul 2025317 PMAQI
2nd Jul 2025298 PMAQI
2nd Jul 2025279 PMAQI
2nd Jul 20252710 PMAQI
2nd Jul 20252711 PMAQI
3rd Jul 20252712 AMAQI
3rd Jul 2025271 AMAQI
3rd Jul 2025272 AMAQI
3rd Jul 2025273 AMAQI
3rd Jul 2025284 AMAQI

25°C14/34°C

3rd Jul 2025235 AMAQI
3rd Jul 2025216 AMAQI
3rd Jul 2025247 AMAQI
3rd Jul 2025258 AMAQI
3rd Jul 2025279 AMAQI
3rd Jul 20252810 AMAQI
3rd Jul 20252911 AMAQI
3rd Jul 20253012 PMAQI
3rd Jul 2025291 PMAQI
3rd Jul 2025292 PMAQI
3rd Jul 2025323 PMAQI
3rd Jul 2025274 PMAQI
3rd Jul 2025275 PMAQI
3rd Jul 2025256 PMAQI
3rd Jul 2025257 PMAQI
3rd Jul 2025248 PMAQI
3rd Jul 2025239 PMAQI
3rd Jul 20252210 PMAQI
3rd Jul 20252611 PMAQI
4th Jul 20252812 AMAQI
4th Jul 2025261 AMAQI
4th Jul 2025262 AMAQI
4th Jul 2025273 AMAQI
4th Jul 2025274 AMAQI

25°C15/33°C

4th Jul 2025235 AMAQI
4th Jul 2025216 AMAQI
4th Jul 2025237 AMAQI
4th Jul 2025238 AMAQI
4th Jul 2025239 AMAQI
4th Jul 20252510 AMAQI
4th Jul 20252411 AMAQI
4th Jul 20252412 PMAQI
4th Jul 2025251 PMAQI
4th Jul 2025242 PMAQI
4th Jul 2025243 PMAQI
4th Jul 2025244 PMAQI
4th Jul 2025235 PMAQI
4th Jul 2025246 PMAQI
4th Jul 2025237 PMAQI
4th Jul 2025258 PMAQI
4th Jul 2025239 PMAQI
4th Jul 20252310 PMAQI
4th Jul 20252611 PMAQI
5th Jul 20253312 AMAQI
5th Jul 2025401 AMAQI
5th Jul 2025422 AMAQI
5th Jul 2025423 AMAQI
5th Jul 2025394 AMAQI

23°C15/31°C

5th Jul 2025375 AMAQI
5th Jul 2025356 AMAQI
5th Jul 2025337 AMAQI
5th Jul 2025328 AMAQI
5th Jul 2025309 AMAQI
5th Jul 20253010 AMAQI
5th Jul 20253011 AMAQI
5th Jul 20252912 PMAQI
5th Jul 2025271 PMAQI
5th Jul 2025292 PMAQI
5th Jul 2025313 PMAQI
5th Jul 2025314 PMAQI
5th Jul 2025305 PMAQI
5th Jul 2025316 PMAQI
5th Jul 2025327 PMAQI
5th Jul 2025328 PMAQI
5th Jul 2025309 PMAQI
5th Jul 20253110 PMAQI
5th Jul 20253111 PMAQI
6th Jul 20253212 AMAQI
6th Jul 2025311 AMAQI
6th Jul 2025322 AMAQI
6th Jul 2025323 AMAQI
6th Jul 2025324 AMAQI

23°C18/31°C

6th Jul 2025305 AMAQI
6th Jul 2025266 AMAQI
6th Jul 2025277 AMAQI
6th Jul 2025288 AMAQI
6th Jul 2025289 AMAQI
6th Jul 20252910 AMAQI
6th Jul 20252811 AMAQI
6th Jul 20252812 PMAQI
6th Jul 2025271 PMAQI
6th Jul 2025272 PMAQI
6th Jul 2025273 PMAQI
6th Jul 2025274 PMAQI
6th Jul 2025275 PMAQI
6th Jul 2025276 PMAQI
6th Jul 2025277 PMAQI
6th Jul 2025278 PMAQI
6th Jul 2025289 PMAQI
6th Jul 20252810 PMAQI
6th Jul 20252811 PMAQI
7th Jul 20252912 AMAQI
7th Jul 2025281 AMAQI
7th Jul 2025282 AMAQI
7th Jul 2025283 AMAQI
7th Jul 2025284 AMAQI

23°C16/32°C

7th Jul 2025245 AMAQI
7th Jul 2025246 AMAQI
7th Jul 2025267 AMAQI
7th Jul 2025258 AMAQI
7th Jul 2025279 AMAQI
7th Jul 20252810 AMAQI
7th Jul 20252811 AMAQI
7th Jul 20252812 PMAQI
7th Jul 2025291 PMAQI
7th Jul 2025282 PMAQI
7th Jul 2025263 PMAQI
7th Jul 2025264 PMAQI
7th Jul 2025265 PMAQI
7th Jul 2025266 PMAQI
7th Jul 2025267 PMAQI
7th Jul 2025298 PMAQI
7th Jul 2025289 PMAQI
7th Jul 20252810 PMAQI
7th Jul 20253011 PMAQI
8th Jul 20253012 AMAQI
8th Jul 2025291 AMAQI
8th Jul 2025302 AMAQI
8th Jul 2025293 AMAQI
8th Jul 2025294 AMAQI

24°C14/34°C

8th Jul 2025315 AMAQI
8th Jul 2025276 AMAQI
8th Jul 2025287 AMAQI
8th Jul 2025288 AMAQI
8th Jul 2025299 AMAQI
8th Jul 20252910 AMAQI
8th Jul 20253011 AMAQI
8th Jul 20253312 PMAQI
8th Jul 2025311 PMAQI
8th Jul 2025312 PMAQI
8th Jul 2025293 PMAQI
8th Jul 2025304 PMAQI
8th Jul 2025305 PMAQI
8th Jul 2025296 PMAQI
8th Jul 2025287 PMAQI
8th Jul 2025288 PMAQI
8th Jul 2025279 PMAQI
8th Jul 20252810 PMAQI
8th Jul 20252911 PMAQI
9th Jul 20253012 AMAQI
9th Jul 2025301 AMAQI
9th Jul 2025292 AMAQI
9th Jul 2025303 AMAQI
9th Jul 2025294 AMAQI

25°C15/35°C

9th Jul 2025275 AMAQI
9th Jul 2025256 AMAQI
9th Jul 2025267 AMAQI
9th Jul 2025278 AMAQI
9th Jul 2025309 AMAQI
9th Jul 20253110 AMAQI
9th Jul 20253411 AMAQI
9th Jul 20253312 PMAQI
9th Jul 2025311 PMAQI
9th Jul 2025282 PMAQI
9th Jul 2025263 PMAQI
9th Jul 2025254 PMAQI
9th Jul 2025255 PMAQI
9th Jul 2025246 PMAQI
9th Jul 2025277 PMAQI
9th Jul 2025288 PMAQI
9th Jul 2025289 PMAQI
9th Jul 20253110 PMAQI
9th Jul 20253011 PMAQI
10th Jul 20253012 AMAQI
10th Jul 2025301 AMAQI
10th Jul 2025292 AMAQI
10th Jul 2025263 AMAQI
10th Jul 2025274 AMAQI

29°C21/37°C

10th Jul 2025235 AMAQI
10th Jul 2025216 AMAQI
10th Jul 2025227 AMAQI
10th Jul 2025228 AMAQI
10th Jul 2025249 AMAQI
10th Jul 20252610 AMAQI
10th Jul 20252711 AMAQI
10th Jul 20252712 PMAQI
10th Jul 2025261 PMAQI
10th Jul 2025272 PMAQI
10th Jul 2025293 PMAQI
10th Jul 2025374 PMAQI
10th Jul 2025425 PMAQI
10th Jul 2025426 PMAQI
10th Jul 2025327 PMAQI
10th Jul 2025308 PMAQI
10th Jul 2025409 PMAQI
10th Jul 20253810 PMAQI
10th Jul 20253611 PMAQI
11th Jul 20253412 AMAQI
11th Jul 2025341 AMAQI
11th Jul 2025352 AMAQI
11th Jul 2025343 AMAQI
11th Jul 2025344 AMAQI

26°C18/32°C

11th Jul 2025365 AMAQI
11th Jul 2025376 AMAQI
11th Jul 2025387 AMAQI
11th Jul 2025408 AMAQI
11th Jul 2025409 AMAQI
11th Jul 20254010 AMAQI
11th Jul 20254011 AMAQI
11th Jul 20254012 PMAQI
11th Jul 2025431 PMAQI
11th Jul 2025382 PMAQI
11th Jul 2025353 PMAQI
11th Jul 2025354 PMAQI
11th Jul 2025355 PMAQI
11th Jul 2025366 PMAQI
11th Jul 2025377 PMAQI
11th Jul 2025378 PMAQI
11th Jul 2025379 PMAQI
11th Jul 20253910 PMAQI
11th Jul 20254411 PMAQI
12th Jul 20254812 AMAQI
12th Jul 2025511 AMAQI
12th Jul 2025502 AMAQI
12th Jul 2025503 AMAQI
12th Jul 2025504 AMAQI

20°C13/27°C

12th Jul 2025585 AMAQI
12th Jul 2025556 AMAQI
12th Jul 2025537 AMAQI
12th Jul 2025538 AMAQI
12th Jul 2025549 AMAQI
12th Jul 20255410 AMAQI
12th Jul 20255411 AMAQI
12th Jul 20255412 PMAQI
12th Jul 2025541 PMAQI
12th Jul 2025522 PMAQI
12th Jul 2025513 PMAQI
12th Jul 2025514 PMAQI
12th Jul 2025515 PMAQI
12th Jul 2025506 PMAQI
12th Jul 2025507 PMAQI
12th Jul 2025508 PMAQI
12th Jul 2025499 PMAQI
12th Jul 20254810 PMAQI
12th Jul 20254811 PMAQI
13th Jul 20254912 AMAQI
13th Jul 2025481 AMAQI
13th Jul 2025482 AMAQI
13th Jul 2025493 AMAQI
13th Jul 2025484 AMAQI

20°C12/27°C

13th Jul 2025405 AMAQI
13th Jul 2025406 AMAQI
13th Jul 2025407 AMAQI
13th Jul 2025398 AMAQI
13th Jul 2025399 AMAQI
13th Jul 20253710 AMAQI
13th Jul 20253911 AMAQI
13th Jul 20254012 PMAQI
13th Jul 2025401 PMAQI
13th Jul 2025402 PMAQI
13th Jul 2025413 PMAQI
13th Jul 2025414 PMAQI
13th Jul 2025405 PMAQI
13th Jul 2025406 PMAQI
13th Jul 2025427 PMAQI
13th Jul 2025418 PMAQI
13th Jul 2025389 PMAQI
13th Jul 20253810 PMAQI
13th Jul 20254011 PMAQI
14th Jul 20254012 AMAQI
14th Jul 2025381 AMAQI
14th Jul 2025372 AMAQI
14th Jul 2025343 AMAQI
14th Jul 2025334 AMAQI

25°C17/32°C

14th Jul 2025255 AMAQI
14th Jul 2025246 AMAQI
14th Jul 2025267 AMAQI
14th Jul 2025278 AMAQI
14th Jul 2025299 AMAQI
14th Jul 20252810 AMAQI
14th Jul 20252911 AMAQI
14th Jul 20253012 PMAQI
14th Jul 2025301 PMAQI
14th Jul 2025292 PMAQI
14th Jul 2025313 PMAQI
14th Jul 2025314 PMAQI
14th Jul 2025305 PMAQI
14th Jul 2025296 PMAQI
14th Jul 2025297 PMAQI
14th Jul 2025298 PMAQI
14th Jul 2025259 PMAQI
14th Jul 20252710 PMAQI
14th Jul 20252611 PMAQI
15th Jul 20252812 AMAQI
15th Jul 2025281 AMAQI
15th Jul 2025272 AMAQI
15th Jul 2025263 AMAQI
15th Jul 2025274 AMAQI

26°C20/35°C

15th Jul 2025255 AMAQI
15th Jul 2025246 AMAQI
15th Jul 2025277 AMAQI
15th Jul 2025298 AMAQI
15th Jul 2025319 AMAQI
15th Jul 20253310 AMAQI
15th Jul 20253511 AMAQI
15th Jul 20253312 PMAQI
15th Jul 2025301 PMAQI
15th Jul 2025312 PMAQI
15th Jul 2025303 PMAQI
15th Jul 2025314 PMAQI
15th Jul 2025295 PMAQI
15th Jul 2025306 PMAQI
15th Jul 2025297 PMAQI
15th Jul 2025298 PMAQI
15th Jul 2025329 PMAQI
15th Jul 20253010 PMAQI
15th Jul 20253111 PMAQI
16th Jul 20253112 AMAQI
16th Jul 2025321 AMAQI
16th Jul 2025322 AMAQI
16th Jul 2025323 AMAQI
16th Jul 2025334 AMAQI

27°C20/35°C

16th Jul 2025355 AMAQI
16th Jul 2025356 AMAQI
16th Jul 2025367 AMAQI
16th Jul 2025388 AMAQI
16th Jul 2025389 AMAQI
16th Jul 20254010 AMAQI
16th Jul 20254011 AMAQI
16th Jul 20254012 PMAQI
16th Jul 2025421 PMAQI
16th Jul 2025412 PMAQI
16th Jul 2025433 PMAQI
16th Jul 2025444 PMAQI
16th Jul 2025465 PMAQI
16th Jul 2025476 PMAQI
16th Jul 2025417 PMAQI
16th Jul 2025398 PMAQI
16th Jul 2025429 PMAQI
16th Jul 20254210 PMAQI
16th Jul 20253911 PMAQI
17th Jul 20253912 AMAQI
17th Jul 2025381 AMAQI
17th Jul 2025362 AMAQI
17th Jul 2025363 AMAQI
17th Jul 2025364 AMAQI

20°C14/28°C

17th Jul 2025375 AMAQI
17th Jul 2025376 AMAQI
17th Jul 2025397 AMAQI
17th Jul 2025408 AMAQI
17th Jul 2025429 AMAQI
17th Jul 20254510 AMAQI
17th Jul 20254711 AMAQI
17th Jul 20254812 PMAQI
17th Jul 2025491 PMAQI
17th Jul 2025492 PMAQI
17th Jul 2025503 PMAQI
17th Jul 2025514 PMAQI
17th Jul 2025515 PMAQI
17th Jul 2025506 PMAQI
17th Jul 2025477 PMAQI
17th Jul 2025468 PMAQI
17th Jul 2025479 PMAQI
17th Jul 20254510 PMAQI
17th Jul 20254511 PMAQI
18th Jul 20254712 AMAQI
18th Jul 2025461 AMAQI
18th Jul 2025462 AMAQI
18th Jul 2025473 AMAQI
18th Jul 2025474 AMAQI

22°C15/30°C

18th Jul 2025465 AMAQI
18th Jul 2025466 AMAQI
18th Jul 2025487 AMAQI
18th Jul 2025498 AMAQI
18th Jul 2025519 AMAQI
18th Jul 20255110 AMAQI
18th Jul 20255011 AMAQI
18th Jul 20255012 PMAQI
18th Jul 2025501 PMAQI
18th Jul 2025502 PMAQI
18th Jul 2025503 PMAQI
18th Jul 2025504 PMAQI
18th Jul 2025505 PMAQI
18th Jul 2025506 PMAQI
18th Jul 2025497 PMAQI
18th Jul 2025488 PMAQI
18th Jul 2025479 PMAQI
18th Jul 20254610 PMAQI
18th Jul 20254711 PMAQI
19th Jul 20254612 AMAQI
19th Jul 2025451 AMAQI
19th Jul 2025432 AMAQI
19th Jul 2025433 AMAQI
19th Jul 2025394 AMAQI

24°C15/34°C

19th Jul 2025355 AMAQI
19th Jul 2025346 AMAQI
19th Jul 2025367 AMAQI
19th Jul 2025358 AMAQI
19th Jul 2025349 AMAQI
19th Jul 20253310 AMAQI
19th Jul 20253511 AMAQI
19th Jul 20253712 PMAQI
19th Jul 2025381 PMAQI
19th Jul 2025382 PMAQI
19th Jul 2025393 PMAQI
19th Jul 2025384 PMAQI
19th Jul 2025385 PMAQI
19th Jul 2025386 PMAQI
19th Jul 2025387 PMAQI
19th Jul 2025398 PMAQI
19th Jul 2025379 PMAQI
19th Jul 20253710 PMAQI
19th Jul 20253611 PMAQI
20th Jul 20253512 AMAQI
20th Jul 2025361 AMAQI
20th Jul 2025372 AMAQI
20th Jul 2025363 AMAQI
20th Jul 2025364 AMAQI

25°C18/33°C

20th Jul 2025295 AMAQI
20th Jul 2025266 AMAQI
20th Jul 2025287 AMAQI
20th Jul 2025288 AMAQI
20th Jul 2025289 AMAQI
20th Jul 20252710 AMAQI
20th Jul 20252611 AMAQI
20th Jul 20252612 PMAQI
20th Jul 2025261 PMAQI
20th Jul 2025282 PMAQI
20th Jul 2025303 PMAQI
20th Jul 2025294 PMAQI
20th Jul 2025295 PMAQI
20th Jul 2025296 PMAQI
20th Jul 2025287 PMAQI
20th Jul 2025278 PMAQI
20th Jul 2025279 PMAQI
20th Jul 20252710 PMAQI
20th Jul 20252811 PMAQI
21st Jul 20252812 AMAQI
21st Jul 2025271 AMAQI
21st Jul 2025262 AMAQI
21st Jul 2025283 AMAQI
21st Jul 2025284 AMAQI

25°C20/34°C

21st Jul 2025255 AMAQI
21st Jul 2025246 AMAQI
21st Jul 2025267 AMAQI
21st Jul 2025278 AMAQI
21st Jul 2025299 AMAQI
21st Jul 20253010 AMAQI
21st Jul 20253111 AMAQI
21st Jul 20253112 PMAQI
21st Jul 2025301 PMAQI
21st Jul 2025302 PMAQI
21st Jul 2025303 PMAQI
21st Jul 2025294 PMAQI
21st Jul 2025285 PMAQI
21st Jul 2025296 PMAQI
21st Jul 2025287 PMAQI
21st Jul 2025268 PMAQI
21st Jul 2025279 PMAQI
21st Jul 20252810 PMAQI
21st Jul 20252811 PMAQI
22nd Jul 20252912 AMAQI
22nd Jul 2025281 AMAQI
22nd Jul 2025282 AMAQI
22nd Jul 2025283 AMAQI
22nd Jul 2025264 AMAQI

25°C20/34°C

22nd Jul 2025235 AMAQI
22nd Jul 2025216 AMAQI
22nd Jul 2025227 AMAQI
22nd Jul 2025238 AMAQI
22nd Jul 2025259 AMAQI
22nd Jul 20252610 AMAQI
22nd Jul 20252811 AMAQI
22nd Jul 20252812 PMAQI
22nd Jul 2025291 PMAQI
22nd Jul 2025282 PMAQI
22nd Jul 2025273 PMAQI
22nd Jul 2025284 PMAQI
22nd Jul 2025275 PMAQI
22nd Jul 2025266 PMAQI
22nd Jul 2025267 PMAQI
22nd Jul 2025268 PMAQI
22nd Jul 2025249 PMAQI
22nd Jul 20252410 PMAQI
22nd Jul 20252411 PMAQI
23rd Jul 20252412 AMAQI
23rd Jul 2025221 AMAQI
23rd Jul 2025232 AMAQI
23rd Jul 2025223 AMAQI
23rd Jul 2025224 AMAQI

25°C20/33°C

23rd Jul 2025205 AMAQI
23rd Jul 2025206 AMAQI
23rd Jul 2025207 AMAQI
23rd Jul 2025208 AMAQI
23rd Jul 2025229 AMAQI
23rd Jul 20252310 AMAQI
23rd Jul 20252411 AMAQI
23rd Jul 20252512 PMAQI
23rd Jul 2025271 PMAQI
23rd Jul 2025272 PMAQI
23rd Jul 2025283 PMAQI
23rd Jul 2025274 PMAQI
23rd Jul 2025275 PMAQI
23rd Jul 2025276 PMAQI
23rd Jul 2025237 PMAQI
23rd Jul 2025248 PMAQI
23rd Jul 2025269 PMAQI
23rd Jul 20252610 PMAQI
23rd Jul 20252611 PMAQI
24th Jul 20252412 AMAQI
24th Jul 2025241 AMAQI
24th Jul 2025252 AMAQI
24th Jul 2025283 AMAQI
24th Jul 2025274 AMAQI

22°C17/29°C

24th Jul 2025285 AMAQI
24th Jul 2025276 AMAQI
24th Jul 2025277 AMAQI
24th Jul 2025278 AMAQI
24th Jul 2025299 AMAQI
24th Jul 20252810 AMAQI
24th Jul 20253011 AMAQI
24th Jul 20253112 PMAQI
24th Jul 2025331 PMAQI
24th Jul 2025332 PMAQI
24th Jul 2025323 PMAQI
24th Jul 2025334 PMAQI
24th Jul 2025335 PMAQI
24th Jul 2025346 PMAQI
24th Jul 2025307 PMAQI
24th Jul 2025318 PMAQI
24th Jul 2025379 PMAQI
24th Jul 20253710 PMAQI
24th Jul 20253611 PMAQI
25th Jul 20253312 AMAQI
25th Jul 2025301 AMAQI
25th Jul 2025322 AMAQI
25th Jul 2025323 AMAQI
25th Jul 2025324 AMAQI

19°C15/28°C

25th Jul 2025345 AMAQI
25th Jul 2025376 AMAQI
25th Jul 2025367 AMAQI
25th Jul 2025388 AMAQI
25th Jul 2025419 AMAQI
25th Jul 20254210 AMAQI
25th Jul 20254111 AMAQI
25th Jul 20254112 PMAQI
25th Jul 2025401 PMAQI
25th Jul 2025392 PMAQI
25th Jul 2025393 PMAQI
25th Jul 2025404 PMAQI
25th Jul 2025425 PMAQI
25th Jul 2025426 PMAQI
25th Jul 2025397 PMAQI
25th Jul 2025378 PMAQI
25th Jul 2025399 PMAQI
25th Jul 20253810 PMAQI
25th Jul 20254011 PMAQI
26th Jul 20254012 AMAQI
26th Jul 2025411 AMAQI
26th Jul 2025412 AMAQI
26th Jul 2025413 AMAQI
26th Jul 2025414 AMAQI

23°C15/33°C

26th Jul 2025445 AMAQI
26th Jul 2025456 AMAQI
26th Jul 2025457 AMAQI
26th Jul 2025448 AMAQI
26th Jul 2025449 AMAQI
26th Jul 20254510 AMAQI
26th Jul 20254411 AMAQI
26th Jul 20254412 PMAQI
26th Jul 2025441 PMAQI
26th Jul 2025432 PMAQI
26th Jul 2025433 PMAQI
26th Jul 2025404 PMAQI
26th Jul 2025405 PMAQI
26th Jul 2025386 PMAQI
26th Jul 2025407 PMAQI
26th Jul 2025428 PMAQI
26th Jul 2025339 PMAQI
26th Jul 20253310 PMAQI
26th Jul 20253311 PMAQI
27th Jul 20253412 AMAQI
27th Jul 2025341 AMAQI
27th Jul 2025342 AMAQI
27th Jul 2025353 AMAQI
27th Jul 2025354 AMAQI

24°C18/34°C

27th Jul 2025275 AMAQI
27th Jul 2025256 AMAQI
27th Jul 2025267 AMAQI
27th Jul 2025268 AMAQI
27th Jul 2025259 AMAQI
27th Jul 20252510 AMAQI
27th Jul 20252511 AMAQI
27th Jul 20252412 PMAQI
27th Jul 2025241 PMAQI
27th Jul 2025252 PMAQI
27th Jul 2025263 PMAQI
27th Jul 2025264 PMAQI
27th Jul 2025285 PMAQI
27th Jul 2025276 PMAQI
27th Jul 2025267 PMAQI
27th Jul 2025268 PMAQI
27th Jul 2025259 PMAQI
27th Jul 20252510 PMAQI
27th Jul 20252511 PMAQI
28th Jul 20252712 AMAQI
28th Jul 2025271 AMAQI
28th Jul 2025282 AMAQI
28th Jul 2025263 AMAQI
28th Jul 2025254 AMAQI

25°C17/34°C

28th Jul 2025235 AMAQI
28th Jul 2025236 AMAQI
28th Jul 2025257 AMAQI
28th Jul 2025268 AMAQI
28th Jul 2025279 AMAQI
28th Jul 20252810 AMAQI
28th Jul 20253111 AMAQI
28th Jul 20253012 PMAQI
28th Jul 2025301 PMAQI
28th Jul 2025292 PMAQI
28th Jul 2025283 PMAQI
28th Jul 2025284 PMAQI
28th Jul 2025275 PMAQI
28th Jul 2025286 PMAQI
28th Jul 2025277 PMAQI
28th Jul 2025278 PMAQI
28th Jul 2025289 PMAQI
28th Jul 20252710 PMAQI
28th Jul 20253011 PMAQI
29th Jul 20253612 AMAQI
29th Jul 2025371 AMAQI
29th Jul 2025402 AMAQI
29th Jul 2025433 AMAQI
29th Jul 2025424 AMAQI

27°C20/34°C

29th Jul 2025475 AMAQI
29th Jul 2025476 AMAQI
29th Jul 2025487 AMAQI
29th Jul 2025478 AMAQI
29th Jul 2025479 AMAQI
29th Jul 20254810 AMAQI
29th Jul 20254711 AMAQI
29th Jul 20254612 PMAQI
29th Jul 2025471 PMAQI
29th Jul 2025462 PMAQI
29th Jul 2025463 PMAQI
29th Jul 2025474 PMAQI
29th Jul 2025485 PMAQI
29th Jul 2025476 PMAQI
29th Jul 2025477 PMAQI
29th Jul 2025468 PMAQI
29th Jul 2025399 PMAQI
29th Jul 20253910 PMAQI
29th Jul 20253811 PMAQI
30th Jul 20253612 AMAQI
30th Jul 2025381 AMAQI
30th Jul 2025382 AMAQI
30th Jul 2025383 AMAQI
30th Jul 2025404 AMAQI

22°C17/28°C

30th Jul 2025355 AMAQI
30th Jul 2025326 AMAQI
30th Jul 2025357 AMAQI
30th Jul 2025368 AMAQI
30th Jul 2025379 AMAQI
30th Jul 20253610 AMAQI
30th Jul 20253611 AMAQI
30th Jul 20253612 PMAQI
30th Jul 2025381 PMAQI
30th Jul 2025392 PMAQI
30th Jul 2025383 PMAQI
30th Jul 2025384 PMAQI
30th Jul 2025385 PMAQI
30th Jul 2025386 PMAQI
30th Jul 2025387 PMAQI
30th Jul 2025388 PMAQI
30th Jul 2025429 PMAQI
30th Jul 20254410 PMAQI
30th Jul 20254511 PMAQI
31st Jul 20254412 AMAQI
31st Jul 2025441 AMAQI

18°C14/23°C

5 AM
12 PM
8 PM
12 AM
4 AM

--°C/°C

Day time
Avg. Highest Time
7 AM - 8 PM

33AQI

14 hours / Day
420 hours / Month
Avg. Lowest Time
6 AM

30AQI

1 hours / Day
30 hours / Month
In the last 30 days, during the daytime, the highest AQI was between 7 AM to 8 PM (Avg. 33), while the lowest AQI was between 6 AM to 6 AM (Avg. 30).
Night time
Avg. Highest Time
12 AM - 11 PM

34AQI

8 hours / Day
240 hours / Month
Avg. Lowest Time
12 AM - 11 PM

34AQI

8 hours / Day
240 hours / Month
In the last 30 days, during the daytime, the highest AQI was between 12 AM to 11 PM (Avg. 34), while the lowest AQI was between 12 AM to 11 PM (Avg. 34).

2025 Days Vs Air Quality

Boulder, Colorado, United States

2025

99%

207

1%

3

Total number of days with different AQI categories in last 212 days in 2025 (153 days remaining)

Good
207 Days
Moderate
3 Days
Poor
0 Days
Unhealthy
0 Days
Severe
0 Days
Hazardous
0 Days

Under WHO’s Safe Air Quality Limits: 99%

Health Risk Level:

Very Low

In 2025, 99% of 212 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

Boulder, Colorado, United States

AQI levels in 2025

AQI
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.

1st January 2025
25AQI
2nd January 2025
31AQI
3rd January 2025
43AQI
4th January 2025
39AQI
5th January 2025
28AQI
6th January 2025
28AQI
7th January 2025
33AQI
8th January 2025
33AQI
9th January 2025
24AQI
10th January 2025
25AQI
11th January 2025
22AQI
12th January 2025
21AQI
13th January 2025
23AQI
14th January 2025
23AQI
15th January 2025
23AQI
16th January 2025
31AQI
17th January 2025
32AQI
18th January 2025
22AQI
19th January 2025
30AQI
20th January 2025
26AQI
21st January 2025
27AQI
22nd January 2025
21AQI
23rd January 2025
23AQI
24th January 2025
22AQI
25th January 2025
22AQI
26th January 2025
38AQI
27th January 2025
47AQI
28th January 2025
37AQI
29th January 2025
37AQI
30th January 2025
30AQI
31st January 2025
26AQI
1st February 2025
19AQI
2nd February 2025
20AQI
3rd February 2025
28AQI
4th February 2025
48AQI
5th February 2025
40AQI
6th February 2025
23AQI
7th February 2025
29AQI
8th February 2025
29AQI
9th February 2025
23AQI
10th February 2025
22AQI
11th February 2025
35AQI
12th February 2025
30AQI
13th February 2025
42AQI
14th February 2025
44AQI
15th February 2025
28AQI
16th February 2025
30AQI
17th February 2025
32AQI
18th February 2025
36AQI
19th February 2025
34AQI
20th February 2025
48AQI
21st February 2025
23AQI
22nd February 2025
22AQI
23rd February 2025
15AQI
24th February 2025
15AQI
25th February 2025
14AQI
26th February 2025
15AQI
27th February 2025
16AQI
28th February 2025
19AQI
1st March 2025
19AQI
2nd March 2025
19AQI
3rd March 2025
20AQI
4th March 2025
19AQI
5th March 2025
17AQI
6th March 2025
20AQI
7th March 2025
17AQI
8th March 2025
17AQI
9th March 2025
14AQI
10th March 2025
19AQI
11th March 2025
17AQI
12th March 2025
19AQI
13th March 2025
19AQI
14th March 2025
22AQI
15th March 2025
17AQI
16th March 2025
22AQI
17th March 2025
23AQI
18th March 2025
20AQI
19th March 2025
17AQI
20th March 2025
22AQI
21st March 2025
18AQI
22nd March 2025
16AQI
23rd March 2025
16AQI
24th March 2025
16AQI
25th March 2025
18AQI
26th March 2025
22AQI
27th March 2025
20AQI
28th March 2025
24AQI
29th March 2025
19AQI
30th March 2025
23AQI
31st March 2025
40AQI
1st April 2025
25AQI
2nd April 2025
17AQI
3rd April 2025
18AQI
4th April 2025
23AQI
5th April 2025
26AQI
6th April 2025
21AQI
7th April 2025
28AQI
8th April 2025
24AQI
9th April 2025
41AQI
10th April 2025
43AQI
11th April 2025
38AQI
12th April 2025
28AQI
13th April 2025
24AQI
14th April 2025
18AQI
15th April 2025
32AQI
16th April 2025
24AQI
17th April 2025
22AQI
18th April 2025
13AQI
19th April 2025
24AQI
20th April 2025
19AQI
21st April 2025
16AQI
22nd April 2025
19AQI
23rd April 2025
29AQI
24th April 2025
53AQI
25th April 2025
25AQI
26th April 2025
23AQI
27th April 2025
26AQI
28th April 2025
16AQI
29th April 2025
16AQI
30th April 2025
16AQI
1st May 2025
15AQI
2nd May 2025
19AQI
3rd May 2025
20AQI
4th May 2025
20AQI
5th May 2025
18AQI
6th May 2025
18AQI
7th May 2025
20AQI
8th May 2025
24AQI
9th May 2025
22AQI
10th May 2025
23AQI
11th May 2025
22AQI
12th May 2025
24AQI
13th May 2025
27AQI
14th May 2025
38AQI
15th May 2025
15AQI
16th May 2025
16AQI
17th May 2025
17AQI
18th May 2025
29AQI
19th May 2025
14AQI
20th May 2025
17AQI
21st May 2025
18AQI
22nd May 2025
22AQI
23rd May 2025
30AQI
24th May 2025
43AQI
25th May 2025
17AQI
26th May 2025
18AQI
27th May 2025
30AQI
28th May 2025
23AQI
29th May 2025
18AQI
30th May 2025
24AQI
31st May 2025
26AQI
1st June 2025
31AQI
2nd June 2025
23AQI
3rd June 2025
20AQI
4th June 2025
34AQI
5th June 2025
34AQI
6th June 2025
27AQI
7th June 2025
23AQI
8th June 2025
32AQI
9th June 2025
45AQI
10th June 2025
36AQI
11th June 2025
27AQI
12th June 2025
25AQI
13th June 2025
26AQI
14th June 2025
35AQI
15th June 2025
29AQI
16th June 2025
27AQI
17th June 2025
29AQI
18th June 2025
26AQI
19th June 2025
30AQI
20th June 2025
33AQI
21st June 2025
32AQI
22nd June 2025
33AQI
23rd June 2025
38AQI
24th June 2025
47AQI
25th June 2025
38AQI
26th June 2025
29AQI
27th June 2025
34AQI
28th June 2025
35AQI
29th June 2025
33AQI
30th June 2025
31AQI
1st July 2025
35AQI
2nd July 2025
29AQI
3rd July 2025
27AQI
4th July 2025
25AQI
5th July 2025
36AQI
6th July 2025
29AQI
7th July 2025
28AQI
8th July 2025
31AQI
9th July 2025
30AQI
10th July 2025
32AQI
11th July 2025
38AQI
12th July 2025
58AQI
13th July 2025
46AQI
14th July 2025
32AQI
15th July 2025
31AQI
16th July 2025
43AQI
17th July 2025
47AQI
18th July 2025
51AQI
19th July 2025
42AQI
20th July 2025
33AQI
21st July 2025
29AQI
22nd July 2025
28AQI
23rd July 2025
26AQI
24th July 2025
32AQI
25th July 2025
41AQI
26th July 2025
44AQI
27th July 2025
27AQI
28th July 2025
28AQI
29th July 2025
48AQI

29AQI

28AQI

20AQI

25AQI

22AQI

31AQI

35AQI

No. of days

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

202527AQI

31
28
31
29
1
31
30
27
2
207
3

Highest AQI recorded in

July

35AQI

Lowest AQI recorded in

March

20AQI

202424AQI

30
1
29
31
30
31
30
26
5
29
2
29
1
28
3
30
31
354
12

Highest AQI recorded in

July

34AQI

Lowest AQI recorded in

May

17AQI

202326AQI

26
2
24
2
31
29
1
26
3
1
30
31
17
5
30
30
1
28
31
333
14
1

Highest AQI recorded in

May

35AQI

Lowest AQI recorded in

December

14AQI

202227AQI

29
1
21
1
30
1
14
2
1
31
27
3
21
2
26
3
31
30
30
292
11
1

Highest AQI recorded in

April

35AQI

Lowest AQI recorded in

July

23AQI

202133AQI

28
2
22
6
27
4
24
3
28
20
6
20
10
14
16
1
24
6
31
29
1
30
1
297
55
1

Highest AQI recorded in

August

55AQI

Lowest AQI recorded in

May

22AQI

202036AQI

3
3
5
1
13
5
25
2
29
1
20
8
19
10
20
10
1
29
30
1
193
41
1

Highest AQI recorded in

March

56AQI

Lowest AQI recorded in

November

24AQI

Most & Least Polluted Years Over the Last 6 Years

Most Polluted Year Recorded
2020(Avg.)
36AQI
Least Polluted Year Recorded
2024(Avg.)
24AQI

Boulder's annual 2025 AQI (27) shows an average percentage change of -5.1% (improved AQI) compared to previous years: 2020 (36), 2021 (33), 2022 (27), 2023 (26), 2024 (24).