Koyacho, Kawaii, Yamagata, Japan Historical Air Quality Analysis
Dive into detailed Air Quality Insights with historical data, monthly patterns, and yearly trends at your fingertips!
February Air Quality Analysis
Koyacho, Kawaii, Yamagata, Japan
AQI Trends: Highest and Lowest
Same Day Analysis (14th February):
On this day, AQI across the 5 years varied significantly: 2026 ranks 1st highest AQI at 65 of Moderate air quality on the same day.
Download 2024 Annual Data
World Air Quality Report

Day & Night AQI Trend: 13th Feb - 14th Feb 2026
Koyacho, Kawaii, Yamagata, Japan
6 AM13th Feb 2026
5 PM
5 AM14th Feb 2026
51AQI
14AQI
48AQI
16AQI
In the last 24 hours,
Koyacho's AQI reached its highest point of 51 at 8 AM during the Day, while the lowest point, 14, was recorded at 5 PM during the Day between 13th Feb and 14th Feb 2026.
Day & Night AQI Trend : Jan - Feb 2026
Koyacho, Kawaii, Yamagata, Japan
2°C-1/3°C
0°C-3/5°C
-2°C-4/1°C
-1°C-5/5°C
-3°C-6/2°C
-5°C-6/-3°C
-5°C-7/-4°C
-4°C-6/-2°C
-4°C-9/-1°C
-5°C-7/-3°C
-4°C-8/-1°C
-2°C-7/3°C
-3°C-5/-1°C
-4°C-5/-2°C
-4°C-5/-2°C
-3°C-5/-1°C
-2°C-4/0°C
-2°C-3/0°C
-3°C-6/1°C
-1°C-6/4°C
2°C0/6°C
1°C-4/3°C
-4°C-5/-2°C
-5°C-7/-3°C
-3°C-6/-1°C
-1°C-6/5°C
0°C-3/3°C
-1°C-3/3°C
0°C-5/4°C
4°C0/9°C
50AQI
27AQI
44AQI
28AQI
2026 Days Vs Air Quality
Koyacho, Kawaii, Yamagata, Japan
91%
41
9%
4
Total number of days with different AQI categories in last 46 days in 2026 (319 days remaining)
Under WHO’s Safe Air Quality Limits: 91%
Health Risk Level:
Very Low
In 2026, 91% of 46 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
Koyacho, Kawaii, Yamagata, Japan
AQI levels in 2026
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
19AQI (US)
17AQI (US)
20AQI (US)
22AQI (US)
23AQI (US)
20AQI (US)
31AQI (US)
24AQI (US)
11AQI (US)
28AQI (US)
28AQI (US)
15AQI (US)
17AQI (US)
14AQI (US)
22AQI (US)
31AQI (US)
40AQI (US)
23AQI (US)
38AQI (US)
17AQI (US)
15AQI (US)
27AQI (US)
51AQI (US)
49AQI (US)
42AQI (US)
30AQI (US)
41AQI (US)
26AQI (US)
21AQI (US)
36AQI (US)
40AQI (US)
39AQI (US)
46AQI (US)
32AQI (US)
20AQI (US)
19AQI (US)
24AQI (US)
13AQI (US)
22AQI (US)
44AQI (US)
53AQI (US)
70AQI (US)
29AQI (US)
30AQI (US)
65AQI (US)
27AQI (US)
36AQI (US)
No. of days
202630AQI (US)
Highest AQI (US) recorded in
February36AQI (US)
Lowest AQI (US) recorded in
January27AQI (US)
202539AQI (US)
Highest AQI (US) recorded in
July51AQI (US)
Lowest AQI (US) recorded in
January32AQI (US)
202438AQI (US)
Highest AQI (US) recorded in
April52AQI (US)
Lowest AQI (US) recorded in
December25AQI (US)
202347AQI (US)
Highest AQI (US) recorded in
September58AQI (US)
Lowest AQI (US) recorded in
January34AQI (US)
202235AQI (US)
Highest AQI (US) recorded in
May42AQI (US)
Lowest AQI (US) recorded in
December26AQI (US)
202132AQI (US)
Highest AQI (US) recorded in
June41AQI (US)
Lowest AQI (US) recorded in
January26AQI (US)
202028AQI (US)
Highest AQI (US) recorded in
August47AQI (US)
Lowest AQI (US) recorded in
December18AQI (US)
Most & Least Polluted Years Over the Last 7 Years
Koyacho's annual 2026 AQI (US) (30) shows an average percentage change of -16.01% (improved AQI (US)) compared to previous years: 2020 (28), 2021 (32), 2022 (35), 2023 (47), 2024 (38), 2025 (39).