Fall Allergy Season Is Starting: What To Expect In Illinois

ILLINOIS — If you've been suffering from itchy eyes or a runny nose, it could be that the arrival of fall is the culprit. The fall allergy season is underway in Illinois, and it’ll take a hard frost to knock down the pollen that makes allergy sufferers feel so miserable.

In Illinois, an average fall pollen level is expected. The pollen season will begin around late September and end in October.

As of Friday, tree pollen and mold were at low levels. Grass pollen and dust and dander were at moderate levels, according to AccuWeather. Ragweed pollen was at a high level, and is expected to remain high through at least Sept. 15.

Allergies are a year-round malady, but are different in the fall than in other seasons. Ragweed is the big culprit, but mold and dust mites are also fall allergy triggers.

“What we see in the fall are allergies to ragweed,” WebMD chief medical officer Dr. John Whyte told AccuWeather. “It blooms between August and November, so we kind of see that peak pollen [occur in] mid- to late September.”

To a lesser extent, mold and dust mites are fall allergy triggers, according to WebMd. Mold spores multiply in wet spots outside, such as piles of damp leaves. The first use of the furnace in the fall sends dust mites idle for months swirling into the air.

Generally, allergy sufferers will breathe easier after the first freeze, when temperatures drop below 28 degrees Fahrenheit for a couple of hours. That won’t happen as early as it does across the eastern third of the country, according to AccuWeather senior meteorologist Alan Reppert.

“We will see the pollen levels really remain high through much of October and even into parts of early November, just due to the lack of temperatures dropping below freezing,” he said, noting that plants and weeds will continue to thrive until then.

Below, AccuWeather gives its fall allergy forecast by region:

Northeast: A weather pattern change in late September and October is expected to bring rain that will ease drought conditions that have persisted throughout much of the summer — but that also means conditions will be ideal for ragweed and mold. Ragweed pollen levels aren’t likely to spike in the East until rainfall increases in October, Reppert said.

Northwest: Intense pollen levels are expected to kick up in the next couple of weeks across eastern Washington, eastern Oregon and through the northern Rockies with the arrival of seasonal rains.

Southwest and Plains: People who live from California to Texas and northward to North Dakota will likely be spared a severe allergy season, but the tradeoff is a prolonged drought that hinders the growth of pollen producing plants.

Gulf Coast: Tropical storms and hurricanes from the Gulf Coast and up the Eastern Seaboard may knock down pollen levels temporarily, but create ideal conditions for the mold spore growth.

Southeast: From eastern Texas east to Georgia and north to Florida, the pollen season is expected to be average, ending in late November.

• Related: 2022 Fall Foliage Peak Map: Use Interactive Tool To Plan Leaf Tours

The symptoms of allergies can mimic those of serious illnesses, including COVID-19, the flu or the common cold. Symptoms of all three include a runny nose, headache and or sore throat, “but itchiness typically means allergies,” Whyte told AccuWeather.

“Itchiness really is a big differentiator,” he said. “The other one is fever. You don't typically get a fever when you're suffering from allergies.”

Until the season ends, keep the windows closed, avoid extended periods of time outdoors, especially when it’s breezy, and use air filters in addition to maintaining a regular medication routine approved by an allergist, Whyte advised.