Milwaukee, WI Pollen Levels Today

Milwaukee's position along Lake Michigan gives the city a humid continental climate with cold winters, warm summers, and lake-effect moisture that shapes a distinct allergy season running roughly from March through October.

Tree pollen kicks off the year in late March and peaks from April into May, with oak, maple, birch, elm, ash, cottonwood, and box elder among the most common offenders across southeastern Wisconsin. As tree counts taper in late May, grass pollen rises and dominates from June through July, driven primarily by timothy, Kentucky bluegrass, orchard grass, and ryegrass—species widely planted throughout lawns, parks, and surrounding farmland.

The transition period in late May and early June often produces overlapping tree and grass pollen, intensifying symptoms for many sufferers.

Weed season follows in mid-August and extends through the first hard frost in October, with short ragweed as the principal trigger, supplemented by lamb's quarters, pigweed, and sagebrush.

Beyond pollen, Milwaukee's lake-driven humidity fuels year-round mold growth—especially Alternaria and Cladosporium spores in summer and fall—while damp basements, decaying leaves, and winter dust mites add indoor triggers.

Overall, Milwaukee's allergy profile is defined by a long, moisture-rich season with strong tree, grass, ragweed, and mold contributions.