In this sentence "it" is used as the subject of an impersonal verb and is therefore a pronoun.
The word "rain" can be a noun or a verb. For example, in the sentence, "I like rain." it is a noun. In the sentence "It is going to rain." it is used as a verb.
It is a noun.
In the rain is a prepositional phrase
The - article rain - noun ruined - verb the - article newspaper - noun
Take your umbrella, it's going to rain today.
Reported or indirect speech is when we report what someone else has said. For example the following sentence are in direct speech: "The rain has stopped" he said. "I will go out" she replied. The same conversation in reported speech: He told her that the rain had stopped. She replied that she would go out.
Rains is a verb, the third person singular conjugation of rain. "It rains every afternoon."Rains can also be a plural noun, the rains, which indicates heavy rainfall or the season of heavy rainfall.
The rain storm did not deter me from going shopping.
Rainstorm is a noun. Nouns are people, places, and things.
I knew it is going to rain today.
It's = It is: You should take your umbrella, it's going to rain.
Humans need to take an active part in the preservation of the rain forests of Guatemala.