Pollen Count in Boston, MA

Boston's allergy profile is shaped by its coastal New England climate, with four distinct seasons delivering a prolonged and varied pollen calendar from early spring through late fall.

Tree pollen kicks off the season in March and peaks in April and May, with oak, birch, maple, cedar, elm, poplar, and ash among the dominant local offenders—oak and birch tend to produce the most intense reactions for Boston-area sufferers.

As tree counts taper in late May, grass pollen takes over through June and into July, driven largely by timothy, Kentucky bluegrass, orchard grass, and ryegrass common to lawns and coastal meadows. The transition period in late spring often creates an overlap between tree and grass pollens, intensifying symptoms for multi-sensitive individuals.

Weed season begins in mid-August and runs through the first hard frost, typically in October, with ragweed as the primary culprit alongside lamb's quarters, pigweed, and plantain.

Beyond pollen, Boston's humid summers and damp springs encourage outdoor and indoor mold growth, while older housing stock contributes to dust mite and cockroach allergen exposure. Urban traffic pollution and occasional ocean-driven humidity swings can further aggravate symptoms.

Overall, Boston is a moderate-to-high allergy city defined by strong tree pollen springs and persistent ragweed-heavy falls.