Grafton County, New Hampshire

AQI 38 · Good

YearMonth

38

Median AQI

56

90th Percentile

113

Max AQI

273

Days with Data

Ranked #3 of 7 counties in New Hampshire (by median AQI, lower is better)

Monthly Median AQI — 2025

Click a bar to view that month's details

AQI Category Breakdown

Adjacent Counties

Belknap County Carroll County Coos County Merrimack County Sullivan County Caledonia County, Vermont Essex County, Vermont Orange County, Vermont Windsor County, Vermont

External Links

Grafton County, New Hampshire on Wikipedia