Is it allergy season in Indiana?

Indiana's position in the agricultural Midwest, combined with its flat topography and warm summers, creates one of the region's most challenging allergy environments. Indianapolis consistently ranks among the AAFA's hardest cities for allergy sufferers. The state's corn and soybean fields contribute to an intense grass pollen season that extends well into summer, followed by a severe ragweed stretch in late summer and fall.

Indiana's relatively flat terrain means pollen disperses widely, but the state's north-south extent creates meaningful seasonal variation. Northern Indiana's cooler climate delays spring pollen by 1–2 weeks compared to the southern tip near the Ohio River.

Central Indiana

Indianapolis and the state's hardest-hit metro

Indianapolis sits in one of the country's most challenging allergy zones. The city's ranking in AAFA top-15 reflects the flat agricultural landscape that allows pollen to travel unimpeded. Tree pollen peaks April–May, then heavy grass through June, followed by a severe ragweed season.

Trees · Apr–MayGrass · May–JunRagweed · Aug–Sep

Northern Indiana

Lake Michigan's moderating influence

Lake Michigan delays spring pollen in the South Bend and Fort Wayne corridors by 1–2 weeks. But the compressed season means higher peak counts when pollen does arrive. Birch and maple are notable in this region. Ragweed is severe across northern counties.

Trees delayed · MayGrass · May–JulLake effect timing

Southern Indiana

Ohio River valley and early spring

The southern tip near Evansville picks up Kentucky's weather patterns, with spring beginning 2–3 weeks earlier than the north. The Ohio River valley traps pollen on still evenings. Tree pollen can begin in late February in favorable years.

Trees · Mar–MayOhio River valley effectGrass · May–Jun

West Central Indiana

Agricultural flatlands intensity

The Wabash Valley and surrounding farmland produce exceptionally high grass pollen counts. With few geographic barriers, pollen from agricultural fields travels broadly. Ragweed in this region is among the state's most intense in late summer.

Grass · Jun–Jul (intense)Ragweed · Aug–SepAgricultural zone

Each row shows a full year of pollen for one region — trees in blue, grasses in green, weeds in amber. Look for where all three rows go quiet at the same time — that's your window.

Oral Allergy Syndrome (also called pollen-food allergy syndrome) causes tingling or mild itching in the mouth when you eat certain raw foods during the relevant pollen season. The proteins in the food are similar enough to the pollen protein that your immune system cross-reacts. Cooking usually deactivates the offending protein, so the same food cooked may cause no reaction.

Oak & Birch pollen

Stone fruits & apples

Apples, peaches, cherries, plums, pears, almonds, hazelnuts, carrots, celery

Peak risk April–May in Indiana. Peeling fruit helps — most of the cross-reactive protein is in the skin.

Grass pollen

Tomatoes, potatoes & melons

Tomatoes, potatoes, kiwi, watermelon, cantaloupe, oranges (in some cases)

Peak risk May–July — Indiana's agricultural regions produce very high grass counts. Symptoms peak during June grass season.

Ragweed

Melons & bananas

Watermelon, cantaloupe, honeydew, banana, zucchini, cucumber, sunflower seeds

Peak risk August–September. Indianapolis is among the Midwest's most ragweed-affected cities.

Not medical advice. If you suspect OAS, speak with an allergist — it can sometimes progress, and symptoms that extend beyond the mouth should be evaluated.