Rain really does have a smell, here's why

Petrichor scent lingers when rain has fallen after a dry period

By Samara Cokinos - Meteorologist

Rain.

ORLANDO, Fla. - Have you ever stepped outside, smelled the air, and thought you could smell the rain coming? You're not crazy, what you smell is known as petrichor. 

The smell of the rain was discovered by two Australian scientists, Isabel Joy Bear and R.G. Thomas, who were studying the smells of wet weather in the 1960s. 

They deemed that smell petrichor, after the Greek term "petra" meaning stone and "ichor" meaning the blood of gods in mythology. 

Petrichor is made up of a few things that you smell in the air when it rains. 

If you're outside when a gust front passes by, the scent in the air that smells like rain is actually ozone.

Lightning in a thunderstorm splits oxygen and nitrogen. These can recombine into nitric oxide, which in turn interacts with other elements in the air and forms ozone.

The sinking air in a thunderstorm that hits the ground known as a downdraft expands outward creating the gust front. 

This is the front that carries the ozone that you smell. You may notice is has a faint chlorine scent to it, but that's what you smell before the rain arrives. 

Once the rain arrives, it's a different story. 

During a dry spell, plants create oils to help inhibit growth so they don't have to compete as much for water. When the rain hits the plant, the odor from the oils is released. 

Sometimes the petrichor may smell musky or earthy. This is from bacteria that lives in the soil known as actinomycetes. The secretion from the bacteria gets wet and that's what you smell. 

So there ya go -- the science behind the smell of rain.  It's the official scent of Central Florida summers. 
 

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