Not just an old wives’ tale: Why you can smell rain, and why it often smells good
If you’ve spent a spring or summer afternoon in the Carolinas, you’ve probably heard someone remark that they can “smell” that rain is coming. And while some may write that concept off as an old wives’ tale, there is actually some scientific truth to the idea.
Liquid water doesn’t necessarily have a scent, but the chemical reactions that happen when rain collides with other compounds created by plants and lightning can give it that earthy, almost sweet smell so many in the South associate with cooling afternoon showers.
The scent even has a scientific name: petrichor.
Here’s what to know about the smell of rain and how it happens:
What is petrichor?
Petrichor, the official monicor for the iconic musk you smell in a rainstorm, got its name from a team of Australian scientists in 1964, the American Chemical Society explains.
“It is caused by the water from the rain, along with certain compounds like ozone, geosmin, and plant oils,” the ACS says.
Ozone comes into play when lightning strikes oxygen and nitrogen molecules, the ACS explains, causing them to split into nitric oxide and ozone. Ozone is then “carried down by droplets of rain to contribute to the scent.”
Another component is geosmin: a compound that’s “released from soil into the air by raindrops” and that the human nose is highly sensitive to. It and other plant compounds are especially detectable when it rains for the first time in a while because they’ve accumulated on plants and in the soil.
Is smelling rain a southern thing?
While afternoon storms are a staple of life in the South, meaning many who’ve lived there have a sentimental attachment to the smell of petrichor, the scent is not limited to any one geographic region.
Of course, that hasn’t stopped plenty of southerners from talking about the art of forecasting rain via their noses and commenting on the weather with unique idioms on social media, in articles and on Youtube.
This story was originally published April 30, 2022 at 10:07 AM.
