I don't think rain is sad.

It's not depressing, gloomy, or scary.

Rain is...

tranquil. It's serene... and, ethereal.

Sometimes it shows up in different moods.

Sometimes it brings friends.

It might bring thunder, lightning, ice or flood. 

Or it might bring sun, gentle snow, or showers.

Sometimes the rain is gentle and makes you feel sleepy.

Sometimes the rain is mad and makes you quiver and shudder.

But for me, rain is exciting. Watching it pour, while you wait for a flash of bright lightning of adrenaline coursing through the dark, blurry night.

It has so many different moods that add to the moment.

That is what rain is to me.