Rain does not smell like rain

The earthy smell that arrives after a dry spell has a name: petrichor. 1

The scent starts on the ground. CSIRO researchers described a yellowish oil held in warm, dry rocks and soil; moisture releases that material into the air. 1

A raindrop also helps launch the smell. MIT researchers used high-speed imaging to observe bubbles forming when drops hit porous ground, rising through the drop, and bursting into tiny airborne aerosols. 2 Their experiments found that light and moderate rain can release more aerosols than heavy rain because fast impacts give bubbles less time to form. 2

The short version is: dry ground stores the material, water loosens it, bubbles lift it, and air carries it to your nose. 12