Why are there so many, songs about Rainbows?

It has been pouring down rain here all week. But a few times I saw a rainbow. Snapped the above photo with my DSi. Rainbows have always held special meaning to me. and I have always loved the song Rainbow Connection.
A rainbow is a promise. First it was a promise from God to Noah that he would never flood the earth again. That no matter how hard or long it rained the earth would be ok. But I feel as though I always see rainbows when I am on the threshold of some new chapter in my life.
When I was 12 and my parents decided to move to Oklahoma I was heartbroken and mad. I was leaving my home, my friends, my grandparents, my cat....everything that I knew and cared about. And I did anything I could think of to raise Hell. The day before we left it poured rain, perfect for my mood and made putting things into the moving truck harder... perfect. But when the rain stopped something amazing was in the sky.

A Double Rainbow.
The only one I have ever seen. I took this picture and never forgot it. That night I felt more at ease, and I was very well behaved, all though teary, the whole next day when we left.
Over the next 5 years when things seemed more than I could bare I always thought of my double rainbow and the promise that everything would be ok.

So what does my rainbow sitings from this week mean? Probly nothing more than a pretty ethereal site after a hard rain. But they still remind me that I am starting a new chapter in my life and no matter what I do...It will be ok.