Spring and summer are usually the first seasons that come to mind when most people think of allergies. But for many people, autumn is just as irritating a season for itchy eyes, runny noses, and scratchy throats. The biggest culprits are ragweed, which makes an appearance by mid-August and can last through October; and mold, which proliferates toward the middle and end of the fall season.

Ragweed is still out in full force during the month of September, according to Devang Doshi, MD, director of the division of pediatric allergy and immunology at Royal Oak Beaumont Hospital in Royal Oak, Michigan. In the northern parts of the U.S. it usually starts winding down by the end of September, but ragweed season begins and ends later in the southern states.

Mold begins to form from the middle of September onward as summer leaves and vegetation decay and die. Autumn rainstorms fuel the decay process, and there’s little relief before winter sets in. “Mold stays until we’re in a hard, deep freeze, when grass and soil feel like cement,” Doshi says. “It’s a really big player [in fall allergies].”

Another factor that may contribute to fall allergies: People tend to spend a lot of time outdoors during this season. The weather is still warm throughout much of the country, but a few degrees cooler than the overly-hot summer months. Many people spend time cleaning up leaves and enjoying outdoor activities, and many folks enjoy leaving windows open during nights that are crisp and cool.

What To Do About Fall Allergies

If you’ve got fall allergies, your best line of defense may be prevention. “To avoid symptoms, avoid the triggers,” says Gary Gross, MD, an allergist at Texas Health Presbyterian Hospital in Dallas.

“If working outside raking leaves, wear a mask. If you have to be outside and cannot avoid the pollen, try [a] saline [nose spray] or one of the medicated nose sprays. These over-the-counter products are widely available, safe and inexpensive.” He adds that there are many good over-the-counter products to control allergy symptoms, and patients should talk to their medical provider about what is best for them.

Other good tips: Keep doors and windows closed, run the air conditioner when possible, and put off outdoor chores on days that have especially high pollen counts.

Devang Doshi, MD, reviewed this article on August 27, 2015.

Gary Gross, MD, reviewed this article on August 26, 2015.


Asthma and Allergy Foundation of America. “Ragweed allergy." Accessed on August 23, 2015.

Doshi, Devang, MD. Phone conversation with source on August 23, 2015.

Gross, Gary, MD. Email correspondence with source on August 22, 2015.