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?
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.