The idea came from the book by H. G. Wells, In the chapter where the invisible man describes how he could be seen in a fog

First Pass. Scene Layout, The idea was an invisible person standing in the fog - - - Second Pass. Basic Materials, The shape is not very visible - - - Third Pass. I thought about rain instead of fog and added a background element
Fourth Pass. First Rain Test - - - Fifth Pass. More Rain, Depth of field and car placement - - - Sixth Pass. Changed camera angle, more rain and better lighting
Seventh Pass. Material for character half wet half invisible, Better rain and water on the road
Final image after compositing