I've looked at the lyrics translated into English and this is what the song means to me: Wherever you are in life, that isn't all there is. Tomorrow will always come, without ever really arriving. Every day you are given the opportunity to make the best of what is in front of you and to lay the foundation to make tomorrow better. We all send our rainbows out into the world hoping they will bring us where we want to go or help us build what we want to build in life, but even if those things don't come to pass the way that we hope, in the end, we have still made rainbows and will never know whose rainy day we have contributed some beauty to.
I hope you enjoy the song as much as I do.