Bad Air Days in Winona County, Minnesota

Not enough data

EPA monitors in Winona County ran on too few days between 2016 and 2025 to give a fair yearly count (about 32% of days covered). Neighbouring counties below are a better guide.

What actually helps here

EPA monitors here ran too few days to give a fair yearly count. Use AirNow for today's air.

The worst days on file

The worst recent year was 2023, with 2 bad days on 119 monitored days.

Date	AQI	Main pollutant
2023-06-29	169	PM2.5
2023-06-05	109	PM2.5
2025-07-30	89	PM2.5
2023-06-14	87	PM2.5
2025-08-02	83	PM2.5

Most days, not the worst ones

Across 1,160 monitored days from 2016 to 2025, the air in Winona County rated Good on 88% of them, more often than the 72% typical of monitored counties, and Moderate on 11%. The median day sat at AQI 23; one day in ten went above 49.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)100%1,160 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	99	83	16	0	0	21	89
2024	122	114	8	0	0	20	63
2023	119	95	22	2	1	28	169
2022	121	113	8	0	0	22	65
2021	116	101	15	0	0	24	80
2020	119	112	7	0	0	22	57
2019	115	102	13	0	0	21	65
2018	113	96	17	0	0	26	80
2017	119	104	15	0	0	22	65
2016	117	106	11	0	0	19	72
2015	120	108	12	0	0	24	76
2014	356	250	105	1	0	40	110
2013	120	101	19	0	0	29	62
2012	120	102	18	0	0	27	86
2011	120	88	32	0	0	29	73
2010	118	89	29	0	0	31	94

*2025 may be a partial year in EPA's file.

Nearby counties on file

How this is counted

A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day.