Pollen Count in Waukegan, IL

Waukegan, located along Lake Michigan in northeastern Illinois, experiences a humid continental climate that produces a pronounced, multi-season allergy calendar. The lakeshore influence moderates temperatures but also traps moisture, creating conditions favorable for both pollen dispersal and mold growth.

Tree pollen kicks off the allergy year in late March and peaks through April and May, with oak, maple, birch, ash, elm, cottonwood, and hickory among the dominant contributors throughout the area's mixed hardwood landscape.

As tree season winds down, grass pollen takes over from late May into July, driven primarily by Kentucky bluegrass, timothy, orchard grass, and ryegrass common to Lake County's lawns, parks, and open fields.

Weed pollen then dominates from mid-August through the first hard frost in October, with short and giant ragweed being the principal offenders, alongside lamb's quarters, pigweed, and sagebrush. Overlap between late-season grasses and early ragweed in August often intensifies symptoms.

Non-pollen allergens are also significant: lake-driven humidity fuels outdoor mold spores (especially Alternaria and Cladosporium) from summer into fall, while indoor dust mites and industrial and traffic-related air pollution add year-round irritation.

Overall, Waukegan's allergy profile is defined by a long, layered season shaped by lake humidity and diverse Midwestern vegetation.