Discover the cities with low ozone in summer based on comprehensive air quality data.
Ranked on summer days only — every summer EPA has published daily AQI for, not the annual average — Honolulu, HI has the cleanest summer air of the metro areas we track: 98.8% of 644 measured summer days at AQI 50 or below, median AQI 23, and 0% of days above AQI 100. Its summer AQI is set most often by fine particulate matter (PM2.5).
| # | City (EPA area) | Summer days measured | Good days | Median AQI | Days over 100 | Worst summer day | Main pollutant |
|---|---|---|---|---|---|---|---|
| 1 | Honolulu, HIUrban Honolulu, HI | 644 | 98.8% | 23 | 0% | 73 | fine particulate matter (PM2.5) |
| 2 | Anchorage, AKAnchorage, AK | 644 | 89.8% | 19 | 1.1% | 163 | fine particulate matter (PM2.5) |
| 3 | Santa Rosa, CASanta Rosa, CA | 644 | 88.8% | 25 | 0% | 97 | fine particulate matter (PM2.5) |
| 4 | Lincoln, NELincoln, NE | 636 | 83% | 40 | 0.3% | 108 | ground-level ozone |
| 5 | Manchester, NHManchester-Nashua, NH | 644 | 78.7% | 40 | 1.4% | 144 | ground-level ozone |
| 6 | Portland, ORPortland-Vancouver-Hillsboro, OR-WA | 644 | 78.4% | 39 | 2.2% | 161 | ground-level ozone |
| 7 | Vancouver, WAPortland-Vancouver-Hillsboro, OR-WA | 644 | 78.4% | 39 | 2.2% | 161 | ground-level ozone |
| 8 | Lubbock, TXLubbock, TX | 618 | 76.7% | 37 | 0.2% | 102 | fine particulate matter (PM2.5) |
| 9 | Orlando, FLOrlando-Kissimmee-Sanford, FL | 644 | 75% | 41 | 0.2% | 115 | fine particulate matter (PM2.5) |
| 10 | Burlington, VTBurlington-South Burlington, VT | 644 | 73.8% | 41 | 0.9% | 160 | fine particulate matter (PM2.5) |
| 11 | Syracuse, NYSyracuse, NY | 644 | 70% | 43 | 1.2% | 258 | ground-level ozone |
| 12 | Billings, MTBillings, MT | 640 | 69.7% | 39 | 1.7% | 167 | fine particulate matter (PM2.5) |
| 13 | Seattle, WASeattle-Tacoma-Bellevue, WA | 644 | 67.4% | 44 | 3% | 195 | fine particulate matter (PM2.5) |
| 14 | Tacoma, WASeattle-Tacoma-Bellevue, WA | 644 | 67.4% | 44 | 3% | 195 | fine particulate matter (PM2.5) |
| 15 | Erie, PAErie, PA | 644 | 66.3% | 44 | 0.9% | 180 | ground-level ozone |
| 16 | Sioux Falls, SDSioux Falls, SD | 643 | 64.7% | 44 | 3.4% | 193 | ground-level ozone |
| 17 | Spokane, WASpokane-Spokane Valley, WA | 644 | 64.4% | 45 | 1.9% | 447 | ground-level ozone |
| 18 | Savannah, GASavannah, GA | 644 | 64.1% | 44 | 0.5% | 131 | fine particulate matter (PM2.5) |
| 19 | Flint, MIFlint, MI | 643 | 63.3% | 44 | 2% | 178 | ground-level ozone |
| 20 | Durham, NCDurham-Chapel Hill, NC | 643 | 62.5% | 46 | 0.5% | 121 | ground-level ozone |
| 21 | Rochester, NYRochester, NY | 644 | 61.8% | 45 | 1.9% | 176 | fine particulate matter (PM2.5) |
| 22 | Charleston, SCCharleston-North Charleston, SC | 644 | 61.8% | 46 | 0.3% | 117 | fine particulate matter (PM2.5) |
| 23 | Sarasota, FLNorth Port-Sarasota-Bradenton, FL | 644 | 61.3% | 44 | 0% | 100 | fine particulate matter (PM2.5) |
| 24 | Charleston, WVCharleston, WV | 644 | 61% | 46 | 0% | 153 | fine particulate matter (PM2.5) |
| 25 | Norfolk, VAVirginia Beach-Norfolk-Newport News, VA-NC | 644 | 60.7% | 46 | 0.6% | 174 | fine particulate matter (PM2.5) |
Source: EPA's published Daily AQI by CBSA files, summarised over every summer in the record. Only areas with at least 400 measured summer 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.
Summer air quality is an ozone story almost everywhere. Ozone is not emitted directly — sunlight cooks it out of traffic and industrial exhaust — so it needs heat, light and stagnant air, and it peaks on the hottest, stillest afternoons. That is why a city can rank well for the year and badly for summer. Wildfire smoke is the other summer driver, and it can push PM2.5 to the top of the dominant-pollutant column in the West for weeks at a time.
Every city's own summer page carries the same statistics for that one place, year by year — start from browse cities or the seasonal guides.
Seasonal air quality varies significantly. These cities maintain good air quality during this season.
Cities are ranked based on AQI levels, dominant pollutants, seasonal patterns, and specific factors relevant to this category.