Ragweed and Fall Pollen in Iowa. What You Need to Know When you Have Fall Seasonal Allergies.
By Laura Jetter, ARNP | September 9, 2026
Fall in Iowa is a magical time with cool temperatures, changing leaves, pumpkin patch activities and outdoor festivals. However, for many people, the fall can also be a time where allergies flare. This is because with the fall season comes weed pollen.
Ragweed: Iowa’s Major Fall Allergy Trigger
Ragweed pollen is one of the most common causes of fall hay fever. Ragweed typically begins releasing pollen in late summer, typically around the time the Iowa State Fair occurs every year. Ragweed and other weeds will continue to release pollen in to the air until a hard frost. This typically occurs sometime in October, with Northern Iowa seeing a hard frost in early October and other regions of Iowa seeing frost later in the month (Elmore, 2013).
Because ragweed pollen is lightweight and easily carried by the wind, it can travel significant distances. In fact, one study found ragweed pollen in samples collected 400 miles offshore out at sea and as high as two miles above the ground (National Institute of Allergy and Infectious Diseases, 2006). This is significant as it demonstrates ragweed pollen’s ability to travel great distances through the air, affecting people in rural and urban areas alike.
Other Fall Allergens
Although ragweed gets most of the attention, it isn’t the only weed that can contribute to fall allergies. Various wind-pollinated weeds such as kochia, russian thistle, pigweed, lamb’s quarter, cocklebur,and sage/marshelder all release pollen during late summer and fall. The exact mix and timing can vary from year to year and from one part of Iowa to another.
Mold spores, although present year round, can also become a seasonal concern during damp fall weather, particularly around fallen leaves and other moist outdoor materials.
How to Reduce Fall Pollen Exposure
If fall allergies are bothering you, a few simple habits may help:
Keep windows closed when pollen counts are high.
Use air conditioning and regularly change air filters.
Shower after spending extended time outdoors to remove pollen from your hair and skin.
Wash bedding regularly and vacuum indoor spaces to reduce pollen buildup.
What if the above strategies are not enough?
If you are allergic to ragweed or other weeds, the fall can be a miserable time with flaring of eczema, asthma, and symptoms such as runny nose, congestion, itchy eyes and more. There are multiple treatment options ranging from medications to immunotherapy (allergy drops) or temporary desensitization for the season with a tablet called Ragwitek. If you are struggling, make an appointment with one of our experienced nurse practitioners to create your custom treatment plan and start getting relief today!
References
National Institute of Allergy and Infectious Diseases. (2006). Airborne allergens—Something in the air. U.S. Department of Health and Human Services, National Institutes of Health. https://www.govinfo.gov/content/pkg/GOVPUB-HE20_3200-PURL-LPS31700/pdf/GOVPUB-HE20_3200-PURL-LPS31700.pdf
Elmore, R. (2013, August 19). Late-season corn development and frost probabilities. Iowa State University Extension and Outreach, Integrated Crop Management
Want to learn more about allergy drops or Ragwitek? Check out the links below!
Ragwitek allergy tablet: https://ragwitek.com/
Allergy Drops: https://www.allergychoices.com/for-patients/
