ST. LOUIS – What’s that smell? A lot of people across the region woke up Thursday asking that question. Our meteorologists got messages about the musty odor and a post started circulating on the local sub-Reddit searching for answers.

Some people describe the odor as smelling like dog droppings. We’re getting those questions mostly from rural readers.

They’re probably right. One of the most likely explanations is that the smell is from farmers laying manure on the fields during the fall. Farmers will often wait until later in the season to lay a liquid slurry on fields. They’re looking for temperatures around 50 degrees. Anything warmer will cause the nutrients to degrade before winter hits.

That’s not the only thing wafting nasty smells into the air. Plus, you may be more aware of your sense of smell during this time of year.

Theresa Crimmins, director of the USA National Phenology Network, explains that cooler temperatures and crisper air enhance our ability to detect these autumn aromas. Those include mold and decaying leaves.

TOPSHOT – A photograph shows a Gingko biloba trees on a central square in Strasbourg, eastern France, on November 25, 2022. – The Ginko biloba trees, planted between the end of the 19th century and the beginning of the 20th century, were gifts from the Emperor of Japan to Kaiser Wilhelm II. (Photo by PATRICK HERTZOG / AFP) (Photo by PATRICK HERTZOG/AFP via Getty Images)

The distinctive autumn scent we love is the result of leaves, trees, and plants dying and decomposing. While the smell is associated with memories of seasonal change, it’s interestingly derived from the process of decay, even though it may trigger allergies for some.

There may be one more culprit. The seeds of female ginkgo trees drop during a 10-day period around Veterans Day. The decomposing seeds emit a scent often likened to dog poop or rancid butter. The covering of the seeds contains butyric acid, resembling the odor found in the human intestine.