Hermiston, Oregon, United States Historical Air Quality Analysis
Dive into detailed Air Quality Insights with historical data, monthly patterns, and yearly trends at your fingertips!
October Air Quality Analysis
Hermiston, Oregon, United States
AQI Trends: Highest and Lowest
Same Day Analysis (7th October ):
On this day, AQI across the 5 years varied significantly: 2025 ranks 2nd highest AQI at 49 of Good air quality, showing improvement over 2022 on the same day.
Download 2024 Annual Data
World Air Quality Report

Day & Night AQI Trend: 7th Oct - 8th Oct 2025
Hermiston, Oregon, United States
6 AM7th Oct 2025
6 PM
5 AM8th Oct 2025
52AQI
44AQI
59AQI
41AQI
In the last 24 hours,
Hermiston's AQI reached its highest point of 59 at 11 PM during the Night, while the lowest point, 41, was recorded at 6 AM during the Night between 7th Oct and 8th Oct 2025.
Day & Night AQI Trend : Sep - Oct 2025
Hermiston, Oregon, United States
23°C15/33°C
23°C15/33°C
23°C15/32°C
22°C17/30°C
22°C15/30°C
23°C15/33°C
19°C15/24°C
18°C11/27°C
21°C11/31°C
22°C13/33°C
22°C13/32°C
24°C15/34°C
24°C16/34°C
20°C13/25°C
16°C9/24°C
17°C7/28°C
19°C7/32°C
21°C10/33°C
18°C10/26°C
17°C7/29°C
19°C9/30°C
19°C12/28°C
18°C10/27°C
17°C12/24°C
15°C10/23°C
15°C7/25°C
17°C12/23°C
15°C9/23°C
12°C2/23°C
13°C3/26°C
--°C/°C
43AQI
41AQI
46AQI
41AQI
2025 Days Vs Air Quality
Hermiston, Oregon, United States
89%
249
11%
31
Total number of days with different AQI categories in last 281 days in 2025 (84 days remaining)
Under WHO’s Safe Air Quality Limits: 89%
Health Risk Level:
Low
In 2025, 89% of 281 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
Hermiston, Oregon, United States
AQI levels in 2025
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
37AQI
33AQI
22AQI
22AQI
34AQI
21AQI
27AQI
34AQI
32AQI
29AQI
18AQI
21AQI
28AQI
42AQI
50AQI
37AQI
39AQI
28AQI
31AQI
31AQI
45AQI
55AQI
58AQI
51AQI
37AQI
37AQI
39AQI
47AQI
55AQI
66AQI
58AQI
17AQI
25AQI
22AQI
23AQI
24AQI
29AQI
25AQI
24AQI
36AQI
25AQI
23AQI
26AQI
24AQI
30AQI
35AQI
57AQI
56AQI
51AQI
28AQI
22AQI
32AQI
47AQI
28AQI
19AQI
16AQI
20AQI
24AQI
30AQI
33AQI
31AQI
17AQI
18AQI
16AQI
16AQI
18AQI
21AQI
21AQI
18AQI
17AQI
19AQI
16AQI
15AQI
15AQI
14AQI
15AQI
15AQI
29AQI
15AQI
14AQI
15AQI
15AQI
15AQI
20AQI
26AQI
18AQI
18AQI
15AQI
17AQI
16AQI
16AQI
17AQI
16AQI
19AQI
26AQI
25AQI
19AQI
13AQI
13AQI
18AQI
15AQI
16AQI
17AQI
23AQI
28AQI
28AQI
18AQI
21AQI
18AQI
18AQI
13AQI
13AQI
19AQI
27AQI
34AQI
34AQI
24AQI
16AQI
15AQI
18AQI
22AQI
22AQI
15AQI
14AQI
15AQI
18AQI
20AQI
15AQI
23AQI
22AQI
15AQI
15AQI
13AQI
17AQI
17AQI
14AQI
14AQI
14AQI
13AQI
12AQI
13AQI
18AQI
18AQI
18AQI
20AQI
16AQI
15AQI
21AQI
17AQI
18AQI
24AQI
17AQI
16AQI
18AQI
18AQI
18AQI
24AQI
21AQI
25AQI
30AQI
27AQI
29AQI
37AQI
27AQI
21AQI
20AQI
24AQI
22AQI
16AQI
17AQI
19AQI
19AQI
17AQI
21AQI
37AQI
37AQI
21AQI
16AQI
13AQI
16AQI
20AQI
25AQI
22AQI
18AQI
18AQI
20AQI
21AQI
23AQI
26AQI
18AQI
15AQI
18AQI
22AQI
22AQI
21AQI
20AQI
31AQI
36AQI
28AQI
33AQI
37AQI
39AQI
36AQI
34AQI
30AQI
18AQI
15AQI
16AQI
18AQI
21AQI
29AQI
31AQI
42AQI
50AQI
24AQI
27AQI
39AQI
22AQI
16AQI
17AQI
24AQI
28AQI
28AQI
34AQI
31AQI
21AQI
18AQI
13AQI
16AQI
19AQI
20AQI
18AQI
20AQI
27AQI
49AQI
58AQI
56AQI
58AQI
59AQI
59AQI
57AQI
56AQI
55AQI
55AQI
58AQI
64AQI
63AQI
81AQI
88AQI
58AQI
44AQI
33AQI
43AQI
57AQI
52AQI
55AQI
35AQI
21AQI
34AQI
43AQI
38AQI
49AQI
56AQI
34AQI
26AQI
49AQI
55AQI
45AQI
37AQI
45AQI
56AQI
78AQI
35AQI
29AQI
26AQI
39AQI
35AQI
33AQI
30AQI
49AQI
38AQI
29AQI
18AQI
20AQI
17AQI
22AQI
25AQI
34AQI
50AQI
34AQI
No. of days
202528AQI
Highest AQI recorded in
September50AQI
Lowest AQI recorded in
May17AQI
202424AQI
Highest AQI recorded in
August37AQI
Lowest AQI recorded in
May12AQI
202326AQI
Highest AQI recorded in
August54AQI
Lowest AQI recorded in
April13AQI
202228AQI
Highest AQI recorded in
September48AQI
Lowest AQI recorded in
May13AQI
202126AQI
Highest AQI recorded in
August57AQI
Lowest AQI recorded in
May15AQI
202030AQI
Highest AQI recorded in
September42AQI
Lowest AQI recorded in
June23AQI
Most & Least Polluted Years Over the Last 6 Years
Hermiston's annual 2025 AQI (28) shows an average percentage change of 5.2% (worsened AQI) compared to previous years: 2020 (30), 2021 (26), 2022 (28), 2023 (26), 2024 (24).