Can You Really Smell a Storm Coming?

Many people notice a distinct smell before or after rain. The scent comes from a combination of ozone, petrichor, and geosmin—natural compounds released into the air before and during rainfall. Here’s why your nose can detect an approaching storm.

Can People Really Smell a Storm Coming?

Have you ever wondered why we can smell the rain coming? My grandfather could even track squirrels with his sense of smell. What he was best known for, however, was his incredible nose for weather.

He could tell a storm was approaching before anyone else in the county. One of my father’s earliest memories was running to warn neighbors that bad storms were coming so that they could get things covered.

Most of us have probably smelt that lovely fresh, earthy aroma of an approaching rain storm. He could smell it coming and even warn people about the strength and likelihood of tornadoes. (He went nuts once when he smelt a hurricane coming.)

He was an educated man (and became superintendent of the Vanderbilt, Texas school system) but the most educated part of him was his nose. In an era when radio coverage was spotty, especially in the country, the neighborhood practically thought of him as a medicine man.

Now scientists have discovered why people can smell the storms so far away. A sensitive snout is smelling ozone, petrichor and geosmin; in other words, the nose smells oxygen, the debris that raindrops kick up and wet bacteria.

Why Does Lightning Produce an Ozone Smell?

First comes the ozone, the oxygen fried by lightening that changes its chemistry for O2 to O3. This has a sweet, pungent zing and winds carry it down from the upper atmosphere to your waiting nose. If you smell a lot of that—look out!

Ozone (O₃): A gas made up of three oxygen atoms. During thunderstorms, lightning can create small amounts of ozone, and winds may carry it ahead of an approaching storm. Some people notice its sharp, fresh, slightly metallic scent before the rain begins.

What Is Petrichor?

Then comes the raindrops. Scientists discovered that water drops hitting surfaces like soil or leaves knock particles up in the air. A raindrop hitting an uneven surface traps bubbles of air that shoot upwards and burst from the top of the water droplet like fizz in a champagne glass. These bubbles can float long distances before they pop and you can smell the pollens, dirt, oils or city scum. Nature’s champagne is called petrichor.

Petrichor: The pleasant, earthy scent released when rain falls on dry soil, rocks, and other surfaces. The smell comes from natural plant oils that build up during dry weather and tiny particles released into the air when raindrops strike the ground.

What Is Geosmin?

Finally, the wet soil triggers the bacteria or blue-green algae to release geosmin, that great earthy smell so loved by gardeners. 

Geosmin: A naturally occurring compound produced by soil-dwelling bacteria, especially Streptomyces. Geosmin is responsible for the rich, earthy aroma many people notice after a rainstorm and is one of the main reasons freshly watered gardens smell so distinctive.

My grandfather may not have known the names petrichor, geosmin, or ozone, but he understood what his nose was telling him. Today, science confirms that the distinctive smells before and after rain come from real chemical compounds carried through the air—making the familiar scent of an approaching storm both a sensory experience and a fascinating glimpse into how weather works.

Frequently Asked Questions

Why does rain smell good?

Rain releases natural compounds such as petrichor and geosmin into the air, creating the fresh, earthy scent many people enjoy.

What is petrichor?

Petrichor is the pleasant smell produced when rain falls on dry soil and rocks, releasing plant oils and tiny airborne particles.

Can humans smell a storm coming?

Some people notice changes in the air before storms because of ozone carried by storm winds, along with increased humidity and changing atmospheric conditions.

Why does dirt smell after rain?

Moisture causes soil bacteria to release geosmin, which is responsible for the distinctive earthy smell after rainfall.