[General] The sky is getting darker. It's almost rain.

[jasonree123456]

The sky is getting darker. It's almost rain.
The sky is getting darker. It's will rain soon.

Can we say "It's almost rain"?

 

[emsr2d2]

No. They are both incorrect.

It will rain soon.
It's going to rain soon.
I think it will rain soon.
It might rain soon.

We can't say "It's almost raining" - it's either raining or it isn't raining.