This simple mod reduces the amount of rain you'll see in game.
This works with both precipType="LightRain" and precipType="HeavyRain" settings in your weather xml.
The rain will be there, but much less visible as if it was little more than a moderate sprinkle.
Back up your originals, or install them using a Mod Manager like JSGME.
The JSGME compatible folder structure in the zip file shows you where these file are to be installed.