Bad Air Days in Skagit County, Washington: 1 a Year

1 bad air day a year

Fewer bad air days than most monitored US counties. Ranked 593 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly particles: smoke and dust (79% particle days).

Which months to watch

Most bad days here fall in August and October and April. Averaged over 2016 to 2025.

What actually helps 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.

The record for Skagit

In 2000 to 2009 this county averaged 1 bad days a year; in 2016 to 2025, 1. Not much has changed. The worst recent year was 2018, with 8 bad days on 365 monitored days.

Date	AQI	Main pollutant
2018-08-21	190	PM2.5
2022-10-19	183	PM2.5
2018-08-22	171	PM2.5
2018-08-20	167	PM2.5
2022-10-20	139	PM2.5

Most days, not the worst ones

Across 3,506 monitored days from 2016 to 2025, the air in Skagit County rated Good on 92% of them, more often than the 72% typical of monitored counties, and Moderate on 7%. The median day sat at AQI 30; one day in ten went above 47.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)71%2,474 days
ozone29%1,024 days

Skagit County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	363	354	9	0	0	25	57
2024	366	357	9	0	0	26	59
2023	365	336	29	0	0	30	93
2022	365	313	47	5	1	33	183
2021	314	296	17	1	0	28	101
2020	272	266	6	0	0	21	57
2019	365	340	25	0	0	29	59
2018	365	325	32	8	3	32	190
2017	365	325	40	0	0	35	99
2016	366	331	35	0	0	34	80
2015	365	284	80	1	0	39	116
2014	365	319	46	0	0	36	77
2013	365	280	85	0	0	39	64
2012	366	357	9	0	0	31	71
2011	365	345	20	0	0	29	86
2010	365	336	21	8	5	31	205

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

Elsewhere in Washington

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.