Elgin, IL Pollen Levels Today

Elgin, Illinois sits in the Fox River Valley within a humid continental climate, producing a prolonged and varied allergy season shaped by cold winters, wet springs, and warm, muggy summers.

Tree pollen typically initiates the cycle from late March through May, with oak, maple, birch, ash, elm, cottonwood, and walnut serving as the dominant regional contributors; oak and birch often drive the most intense peaks in mid-to-late April.

As tree pollen wanes, grass pollen rises from mid-May through July, with Kentucky bluegrass, timothy, orchard grass, and ryegrass common throughout area lawns, parks, and the open prairie corridors along the Fox River.

Weed season follows from August through the first hard frost in October, dominated by ragweed, which thrives in Illinois farmland and disturbed roadsides, alongside lamb's quarters, pigweed, and sagebrush. Late-summer overlap between lingering grasses and emerging ragweed frequently intensifies symptoms in August.

Beyond pollen, Elgin's humidity fosters persistent outdoor mold spores—especially Alternaria and Cladosporium—peaking in late summer and fall, while indoor dust mites thrive during heating season. Proximity to I-90 traffic and occasional agricultural drift can add particulate irritants.

Overall, Elgin's allergy profile is defined by a lengthy, mold-heavy, ragweed-dominant season layered over classic Midwestern tree and grass exposure.