Did you ever notice that you can smell rain? Usually, you smell it better after the rain, but if you are a highly trained naturalist, or Aragorn son of Arathorn, Elessar, the Elfstone, Dúnadain, the heir of Isildur Elendil's son of Gondor, or something, you can smell it before it rains. During the rain you are usually inside smelling other things.
It is called Petrichor. That word comes from ancient Greek for rock (obviously) and God Blood. That makes sense because with all the gods up in the sky, a certain amount of God Blood would fall to the earth when it rains.
Anyway, I came across this video on Petrichor, possibly explaining it.
So, basically, you are smelling raindrop spit.
Well, what else would it be supposed to smell like?
Of course there is an obvious reason why wet concrete, wet grass, wet roses, wet humans, and wet sheep all smell completely different.
yea, rain in spring, summer and autumn smell different. also snow in near zero and way under freezing point if your nose is not runny.
enjoy reading/seeing the nature of tme earth and its creatures