IL · Allergy Season Guide
Illinois Allergy Season Guide
Illinois experiences a humid continental climate with hot, humid summers and cold, snowy winters.
Summary
Illinois has 0 active PollyMap collection sites, and is seeking partners in 6 additional cities. Tree pollen typically dominates early spring, grass pollen peaks in late spring and early summer, and weed pollen (including ragweed) extends from late summer through fall.
PollyMap collection status across Illinois
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Test the air at your own home in Illinois
No allergy clinic is reporting from Illinois yet. Until one does, you can order your own PollyKit — a simple air sampler you hang outdoors or indoors. Send it back and the PollyKit Lab shows you exactly what's floating in your air.
- Pollen from local trees, grasses and weeds
- Airborne mold spores
- Dust mites and other indoor allergens
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See which pollen and mold are in your yard this season.
Or hang it indoors
Check bedrooms and living spaces for mold, dust mites and more.
Statewide allergy overview
Illinois experiences a humid continental climate with hot, humid summers and cold, snowy winters.
Maple, birch, oak, and ash drive the spring tree season. Grass pollen peaks in late May and June, and ragweed dominates from mid-August through the first hard frost.
Heavy leaf litter, agricultural activity, and humid summers produce very high outdoor mold counts from late summer through fall.
Allergy patterns vary by elevation and proximity to coast or mountains within Illinois, but most of the state shares a common seasonal rhythm of spring tree pollen, summer grass pollen, and late-summer to fall weed pollen.
Illinois allergy calendar
Month-by-month intensity for the four major airborne allergen categories.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tree | Low | Mod | High | V.High | V.High | High | Mod | Low | Low | Low | Low | Low |
| Grass | — | — | Low | Mod | High | V.High | High | Mod | Low | Low | — | — |
| Weed | Low | Low | Low | Mod | Mod | Mod | High | V.High | V.High | High | Mod | Low |
| Mold | Low | Low | Mod | Mod | High | High | V.High | V.High | V.High | High | Mod | Low |
Top weed pollens
Top airborne molds
Major city guides in Illinois
Latest PollyMap reports for Illinois
Frequently asked questions
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