It’s rain­ing. Is god tak­ing a whiz? Are the angels hav­ing a group show­er? Is it Novem­ber and Axl is singing again? Did all those naked women doing a rain dance the oth­er day actu­al­ly work? Have the clouds got­ten heavy and burst?

Well, yes actu­al­ly. But there’s one ques­tion about rain I real­ly want­ed to find out about: What caus­es the rain smell during/after rain?

As it turns out, there are many rea­sons for the smell. The main rea­son is that bac­te­r­i­al spores called Actin­o­mycetes rise up when it rains into the air like an aerosol spray and have a dis­tinc­tive pleas­ant earthy smell.

Anoth­er smell con­trib­u­tor is the vari­ety of chem­i­cals that are rained down on us, after our indus­tries and auto­mo­biles have expelled them into the atmos­phere. Trees can also be a fac­tor as they exude rich oils and sap which the rain wash­es down to pro­duce a smell.