Evanston, IL Pollen Levels Today

Evanston, Illinois, situated along Lake Michigan just north of Chicago, experiences a humid continental climate that produces a distinct, multi-phase allergy season stretching from early spring through the first hard frost.

Tree pollen kicks off the year, typically emerging in late March and peaking in April and May, with oak, maple, birch, ash, cottonwood, elm, and walnut being the dominant culprits along Evanston's tree-lined streets and lakefront parks.

As tree counts taper, grass pollen takes over from mid-May through July, driven largely by Kentucky bluegrass, timothy, orchard grass, and perennial ryegrass—species widespread in area lawns, parkways, and prairie remnants.

The transition period in late May and June often sees tree and grass pollens overlap, intensifying symptoms for many sufferers.

Weed season then dominates from August through October, with ragweed being the primary offender, joined by lamb's quarters, pigweed, and plantain.

Beyond pollen, Evanston's lake-influenced humidity fosters significant outdoor mold growth, particularly in leaf litter during damp fall weeks, while indoor dust mites thrive year-round in heated winter interiors.

Proximity to Chicago also means urban air pollution can compound respiratory irritation.

Overall, Evanston's allergy profile is characterized by a long, layered pollen calendar amplified by lakefront humidity and persistent mold pressure.