Practically speaking rain is water that is falling from the sky, thus sharing some of its symbolic meaning with water - Word and/or Spirit. Rain can also be a word play with its homonym "reign", or represent something that grants authority or rules in a persons life or to speak of the Reign of God in the earth.
* Symbol meanings provided by www.mydreamstories.com should not be used as a dream dictionary. They are for reference only and both dreamer and interpreter should be careful to listen to the voice of Holy Spirit as to what any particular symbol means in any specific dream