Best Air Quality in Winter

Discover the cities avoiding winter pollution based on comprehensive air quality data.

The short answer

Ranked on winter days only — every winter EPA has published daily AQI for, not the annual average — Santa Fe, NM has the cleanest winter air of the metro areas we track: 99% of 629 measured winter days at AQI 50 or below, median AQI 38, and 0% of days above AQI 100. Its winter AQI is set most often by ground-level ozone.

US metro areas ranked by winter air quality, EPA daily AQI
#City (EPA area)Winter days measuredGood daysMedian AQIDays over 100Worst winter dayMain pollutant
1Santa Fe, NMSanta Fe, NM62999%380%58ground-level ozone
2Lubbock, TXLubbock, TX59296.8%160%161fine particulate matter (PM2.5)
3Amarillo, TXAmarillo, TX63296%350.3%138ground-level ozone
4Manchester, NHManchester-Nashua, NH63295.7%360%66ground-level ozone
5Honolulu, HIUrban Honolulu, HI63295.3%340.2%117ground-level ozone
6Cheyenne, WYCheyenne, WY63295.1%390%77ground-level ozone
7Colorado Springs, COColorado Springs, CO63291.9%420%67ground-level ozone
8Sioux Falls, SDSioux Falls, SD63286.6%330%94ground-level ozone
9Atlantic City, NJAtlantic City-Hammonton, NJ63185.4%340%77fine particulate matter (PM2.5)
10Billings, MTBillings, MT61284.8%310%77fine particulate matter (PM2.5)
11Santa Rosa, CASanta Rosa, CA63279.3%360%83fine particulate matter (PM2.5)
12Burlington, VTBurlington-South Burlington, VT63278.6%390%98ground-level ozone
13Syracuse, NYSyracuse, NY63277.7%370%74fine particulate matter (PM2.5)
14Fargo, NDFargo, ND-MN63277.5%350.5%139fine particulate matter (PM2.5)
15Norfolk, VAVirginia Beach-Norfolk-Newport News, VA-NC63277.5%360%76fine particulate matter (PM2.5)
16Virginia Beach, VAVirginia Beach-Norfolk-Newport News, VA-NC63277.5%360%76fine particulate matter (PM2.5)
17Charleston, WVCharleston, WV62974.7%390%75fine particulate matter (PM2.5)
18Orlando, FLOrlando-Kissimmee-Sanford, FL63273.6%420.5%149fine particulate matter (PM2.5)
19Erie, PAErie, PA59872.9%380%87fine particulate matter (PM2.5)
20Greensboro, NCGreensboro-High Point, NC63272.8%360%87fine particulate matter (PM2.5)
21Portland, MEPortland-South Portland, ME62971.5%400.2%109fine particulate matter (PM2.5)
22Sarasota, FLNorth Port-Sarasota-Bradenton, FL63270.6%440%84fine particulate matter (PM2.5)
23Laredo, TXLaredo, TX63270.1%420%96fine particulate matter (PM2.5)
24Fort Collins, COFort Collins, CO63269.5%470.2%121ground-level ozone
25Lansing, MILansing-East Lansing, MI63269.1%380%92fine particulate matter (PM2.5)

Source: EPA's published Daily AQI by CBSA files, summarised over every winter in the record. Only areas with at least 400 measured winter days (roughly four full seasons) are ranked. Percentages are shares of those measured days, so a long record and a short one are compared on the same footing. Figures are EPA's published annual AQI summaries by metropolitan area (Annual AQI by CBSA, 2019–2025), retrieved 2026-09-07. The daily AQI EPA summarises is the highest value any monitor in the area reported that day, so these are metro-area readings, not statewide or rural ones.

Why winter is different

Winter air quality is a particle story. Cold, still, clear nights create temperature inversions — a lid of warm air that traps everything emitted underneath it — and the sources underneath are combustion: vehicle exhaust, home heating and wood smoke. Valleys and basins are worst affected, which is why the winter ranking reorders the annual one so sharply.

Every city's own winter page carries the same statistics for that one place, year by year — start from browse cities or the seasonal guides.

Why Air Quality Matters

Seasonal air quality varies significantly. These cities maintain good air quality during this season.

Selection Criteria

Cities are ranked based on AQI levels, dominant pollutants, seasonal patterns, and specific factors relevant to this category.