Detroit, MI Pollen Levels Today

Detroit's allergy profile is shaped by its humid continental climate, proximity to the Great Lakes, and a mix of urban density and surrounding deciduous forests, producing a long and layered pollen season that stretches from early spring through the first hard frost.

Tree pollen launches the season in late March and peaks in April and May, with oak, maple, birch, cottonwood, ash, elm, and mulberry as the dominant culprits across the metro area.

As trees taper in late May, grass pollen takes over through June and July, driven largely by timothy, Kentucky bluegrass, orchard grass, and ryegrass common to Michigan lawns and open fields.

By mid-August, weed pollen dominates, led by ragweed—which thrives in southeastern Michigan's roadsides and vacant lots—along with lamb's quarters, pigweed, and plantain, typically peaking in early September. The overlap between late grass and early ragweed in August often intensifies symptoms for sensitive individuals.

Detroit's humidity also fuels significant outdoor and indoor mold, especially from leaf litter in fall and damp basements, while urban air pollution and vehicle emissions can aggravate respiratory reactions.

Overall, Detroit's profile is defined by a prolonged, tri-seasonal pollen cycle compounded by persistent mold and urban air-quality pressures.