Random Kanji symbol musings: 零 - れい, ゼロ

Seems to be used less as the numerical idea of zero and more as the idea of zero or nothing, although I haven't encountered this in my limited time reading Japanese yet so maybe not. Also, why does it have the rain radical in it? 雨 What's the connection?

Difficulty in remembering 7/10. Likability 4/10.