No surprise really, usage goes down when it is cold, or when it rains or when it is dark. But it's nice to see how much those factors matter. Not as much as some critics like to contend. This is certainly not a direct correlation to biking in general (for one thing, CaBi is closed when it snows, but personal bikes are not), but the two probably have more in common than not. I maintain my belief that one benefit of bike sharing is the massive amount of data it provides to transportation researchers.