Pleuvoir
I saw the sentence " il va pleuvoir"

Is " pleuvoir " infinitive? or we use this form for future?

the meaning of the sentence is
1) it's going to rain
or
2) It's going to be rainy

I read this somewhere and I don't get it? if we use "pleuvoir" for the future why it sais "pleuvra" ?

Present Future Imperfect
il pleut pleuvra pleuvait

Thank you in advance.

Question

Pleuvoir
I saw the sentence " il va pleuvoir"

Is " pleuvoir " infinitive? or we use this form for future?

the meaning of the sentence is 
     1) it's going to rain  
     or
     2) It's going to be rainy

I read this somewhere and I don't get it? if we use "pleuvoir" for the future why it sais "pleuvra" ?

Present	Future	Imperfect
il   	pleut	pleuvra	pleuvait

Thank you in advance.

Answer

Pleuvoir is the infinitive. You use the infinitive because you have already conjugated the verb aller in the sentence "Il va pleuvoir."

When there are two verbs on after the other, the first is conjugated and the second is in the infinitive

The va + infinitive is used when something will happen in the near future. 
For example, you look outside and notice the sky is grey and say "Il va pleuvoir."

Answer

"Il va pleuvoir" is in the near future (It is going to rain)

You conjugate the near future using:
- the verb 'aller' in the present tense (vais, vas, va, allons, allez, vont) + a verb in the infinitive

Here, the verb in the infinitive is 'pleuvoir' (to rain).

"Il pleuvra" is in the future simple (It will rain)
"Il pleuvait" in in the imperfect (It was raining)

And if you ever need them, here are a couple more:

"Il pleut" is in the present tense (it's raining)
"Il a plu" is in the passé composé, past tense (it rained)

Hope it makes more sense now :)

Answer

"il va pleuvoir" (it is going to rain) and "il pleuvra" (it will rain) are two types of future tense.