Petrichor

The smell of earth after rain

Aug 23, 2026

Petrichor: the smell of rain on dry ground from petra - stone, and ichor - the blood of the gods, with a person enjoying the smell in Richmond Park as the rain comes down. — Aaah, smelling petrichor in that place makes me happy. Prints of this (with/without title)

Hello!

The smell of rain—I love it. Who doesn’t? And there’s a name for it: Petrichor.

Petrichor is the earthy smell released when rain falls on dry ground, especially after a long warm spell.

In 2026, here in the UK, after a long, hot and unusually dry summer, we finally had rain. Petrichor hit me hard and gloriously in the local park this week as the rain splashed the dry earth and grass after so long.

Like apricity, petrichor is an evocative name for a beautiful sensation.

More about petrichor below.

Have a great week

Jono

On Petrichor

The name petrichor was coined by Australian scientist Richard (Dick) Thomas who researched the phenomenon with Isabel Joy Bear. They published their findings in the journal Nature in 1964. Thomas formed the name from the Greek words:

petra, meaning stone, and
ichor, for the golden fluid that ran in the veins of the gods

They describe it in a later paper:

‘Petrichor’, well known to mineralogists as argillaceous odour, is commonly observed as the pleasant and refreshing odour which frequently accompanies the first rains after a warm dry period.

What Makes it?

Much of the earthy smell after a rainstorm or shower comes from geosmin, a compound produced by microorganisms in the soil that humans are remarkably sensitive to.

Geosmin, along with other aromatic compounds such as plant oils, is released into the air during rain. This happens when tiny air bubbles trapped by raindrops rise and burst through the droplet in a process with the excellent name splash-induced aerosolisation. It’s one way that bacteria in the soil spread.

You can read more technical information than you ever wanted to know about the bacteria and production of geosmin in Petrichor and Actinomycetes: The Smell of Rain Explained.

We discussed petrichor on the podcast with Grant Snider where he shared his lovely series, Words of Wonder.

I hope you get to enjoy some petrichor this week, too.