Weather Tidbits: The Smell of Rain

This edition of Weather Tidbits discusses what causes the smell of rain. You may have caught this distinct scent from a passing downpour or thunderstorm during the summer. This smell can be one of three things. One factor could be the scent produced by soil-dwelling bacteria that secrete geosmin when producing spores. An earthly-smelling chemical is then released when raindrops come into contact with the geosmin. The oils secreted from plants during dry periods can also produce the smell. The rain releases compounds from those oils that we smell called petrichor. Lastly, the smell may be produced via the splitting of oxygen molecules into individual atoms. Those atoms can combine with oxygen molecules to make ozone. This can create a distinct odor before a thunderstorm occurs.