Wenatchee, WA Air Quality

EPA monitor data through 2025 · Updated September 02, 2026 · Methods

In 2025, Wenatchee, WA recorded 14 days above an Air Quality Index of 100, the level at which EPA begins warning sensitive groups, out of 365 days with monitoring data. The rest of the year was 254 Good days and 97 Moderate days. Most of the bad days were driven by fine particles. Under the AQI rules that applied before 2013, the same air would have scored 12 days. Since 2005, unhealthy days are 500% higher on a consistent definition.

Unhealthy days, 2025
14
AQI above 100
Same air, pre-2013 rules
12
for comparison with older reports
Good-air days
254
AQI 50 or below
Days monitored
365
full year

Unhealthy days by year, scored two ways

EPA changed what an AQI of 100 means in 2013 and again in 2015, so a count published before those changes is not comparable to one published after. Each panel below applies a single fixed rulebook to every year, so each is internally consistent. Why this matters.

Scored by today's rules

Wenatchee, WA: days above AQI 100 by year, current rules 0 6 12 18 24 2000 2005 2010 2015 2020 2025 2000: 0 days (incomplete monitoring) 2001: 0 days (incomplete monitoring) 2002: 0 days (incomplete monitoring) 2003: 0 days (incomplete monitoring) 2004: 0 days (incomplete monitoring) 2005: 2 days 2006: 2 days 2007: 0 days 2008: 1 days 2009: 0 days 2010: 2 days 2011: 7 days 2012: 25 days 2013: 0 days 2014: 8 days 2015: 3 days 2016: 0 days 2017: 21 days 2018: 25 days 2019: 1 days 2020: 12 days 2021: 5 days 2022: 23 days 2023: 5 days 2024: 5 days 2025: 14 days

Scored by the pre-2013 rules

Wenatchee, WA: days above AQI 100 by year, pre-2013 rules 0 6 12 18 24 2000 2005 2010 2015 2020 2025 2000: 0 days (incomplete monitoring) 2001: 0 days (incomplete monitoring) 2002: 0 days (incomplete monitoring) 2003: 0 days (incomplete monitoring) 2004: 0 days (incomplete monitoring) 2005: 2 days 2006: 0 days 2007: 0 days 2008: 0 days 2009: 0 days 2010: 1 days 2011: 4 days 2012: 23 days 2013: 0 days 2014: 5 days 2015: 3 days 2016: 0 days 2017: 18 days 2018: 24 days 2019: 0 days 2020: 12 days 2021: 5 days 2022: 19 days 2023: 5 days 2024: 3 days 2025: 12 days
Faded columns mark years with fewer than 300 monitored days, where the count is not comparable.

What 2025 looked like

Air quality categoryDaysShare of days with an AQI
Good25470%
Moderate9727%
Unhealthy for sensitive groups51%
Unhealthy or worse92%

Median AQI 35 · 90th-percentile AQI 68 · worst day 233. Scored under current rules, out of 365 days with an AQI.

What drove the unhealthy days

Of the 14 days above 100 in 2025, 0 were driven by ozone and 14 by fine particles. The two behave differently. Ozone peaks on hot sunny afternoons; fine particles now spike mainly with wildfire smoke.

The unhealthy days in 2025

Every day the index passed 100, what it reached, and which pollutant drove it. 2 of these 14 would not have counted as unhealthy under the pre-2013 rules.

DatePeak AQIDriven byPre-2013 score
Sep 4106Fine particles 94 (not unhealthy)
Sep 5153Fine particles 135
Sep 6172Fine particles 162
Sep 23135Fine particles 118
Sep 24233Fine particles 209
Sep 25117Fine particles 104
Sep 26164Fine particles 156
Sep 28180Fine particles 169
Sep 29166Fine particles 158
Oct 6168Fine particles 159
Oct 7155Fine particles 142
Oct 8162Fine particles 154
Oct 9106Fine particles 94 (not unhealthy)
Oct 10134Fine particles 118

Statewide context

Wenatchee, WA sits in Washington.

Days in each air quality category, by year

How many days fell in each AQI category, for every year with an AQI on record. Categories are scored under EPA's current breakpoints. A year with fewer than 300 days is marked, because a short year lowers every count for reasons that have nothing to do with the air.

YearGoodModerate Unhealthy for sensitive groupsUnhealthy or worse Days with an AQI
2000 (partial) 8500 085
2001 (partial) 8730 090
2002 (partial) 7600 076
2003 (partial) 4100 041
2004 (partial) 67550 0122
2005 2211262 0349
2006 1981652 0365
2007 2241410 0365
2008 2061591 0366
2009 2301350 0365
2010 2511122 0365
2011 2331236 1363
2012 21312810 15366
2013 2301350 0365
2014 2341206 2362
2015 2431163 0362
2016 284820 0366
2017 2361089 12365
2018 244968 17365
2019 2581061 0365
2020 274801 11366
2021 279812 3365
2022 246968 15365
2023 280801 4365
2024 293684 1366
2025 254975 9365

Good is AQI 0–50, Moderate 51–100, Unhealthy for sensitive groups 101–150. “Unhealthy or worse” combines the Unhealthy, Very Unhealthy and Hazardous categories, which are shown together because most areas record too few of each to report separately. The four columns sum to the last one by construction. These counts exclude sulphur dioxide, following EPA, which drops SO₂ from county and metro summaries because it is too localized to describe a whole area.

The full series

The same years scored two ways, with the pollutant that drove the days above 100. EPA's files record which pollutant set each day's AQI; they do not attribute days to wildfire smoke, so no column here claims to.

YearUnhealthy days, current rulesOf which ozone Of which fine particlesPre-2013 rulesDays monitored
20000 0 0 085
20010 0 0 090
20020 0 0 076
20030 0 0 041
20040 0 0 0122
20052 0 2 2349
20062 0 2 0365
20070 0 0 0365
20081 0 1 0366
20090 0 0 0365
20102 0 2 1365
20117 0 7 4363
201225 0 25 23366
20130 0 0 0365
20148 0 8 5362
20153 0 3 3362
20160 0 0 0366
201721 0 21 18365
201825 0 25 24365
20191 0 1 0365
202012 0 12 12366
20215 0 5 5365
202223 0 23 19365
20235 0 5 5365
20245 0 5 3366
202514 0 14 12365

Sources