Bad Air Days in La Crosse County, Wisconsin: 1 a Year

1 bad air day a year

Fewer bad air days than most monitored US counties. Ranked 632 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly particles: smoke and dust (64% particle days).

When the bad days come in La Crosse

Most bad days here fall in June. Averaged over 2016 to 2025.

Is a purifier worth it here?

Bad air days are rare here. A standard furnace filter is enough; no purifier needed for outdoor air.
On the odd bad day, check AirNow and keep windows shut.

Better or worse than it was

The worst recent year was 2023, with 10 bad days on 339 monitored days.

Date	AQI	Main pollutant
2023-06-28	181	PM2.5
2023-06-27	169	PM2.5
2023-06-05	157	PM2.5
2023-06-04	153	PM2.5
2023-06-29	153	PM2.5

The air on a normal day

Across 3,281 monitored days from 2016 to 2025, the air in La Crosse County rated Good on 74% of them, close to the 72% typical of monitored counties, and Moderate on 26%. The median day sat at AQI 41; one day in ten went above 61.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)56%1,822 days
ozone44%1,459 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	198	185	13	0	0	37	90
2024	205	197	8	0	0	37	67
2023	339	199	130	10	5	45	181
2022	365	271	94	0	0	41	85
2021	365	240	124	1	0	43	110
2020	364	255	109	0	0	42	93
2019	365	274	91	0	0	39	85
2018	365	256	109	0	0	43	97
2017	360	268	92	0	0	41	87
2016	355	288	67	0	0	37	87
2015	361	280	81	0	0	40	98
2014	358	266	92	0	0	40	98
2013	361	191	170	0	0	49	86
2012	316	181	133	2	0	47	105
2011	316	207	109	0	0	44	100
2010	310	216	93	1	0	42	110

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

Elsewhere in Wisconsin

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.