Sometimes a rainy day picture never appears as convincing as it really was. Enter Photoshop!

With our image opened in Photoshop call up the layers palette Window >Show Layers or hit F7 on the keyboard. Now duplicate the image by dragging it over the Create New Layer tab (dia 1) and re-name it Rain. by double clicking on the new layer in the Layers Pallet and typing Rain in the Layer Option palette window (image 2 naming).

Working on our new Rain layer we need to add some noise - Filter > Noise >Add Noise, and click the Gaussian and Monochromatic buttons within the 'noise palette'. Try experimenting with the settings, but for this image an amount of 100 was chosen. (dia 3 noise)

To make the rain more realistic add Motion Blur, Filter> Blur> Motion Blur, and selecting an angle to look like falling rain. An angle of 67 and a distance of 16 pixels were selected, but try experimenting with different settings you may find some that suit your image (dia. 4 blur).