Is there a mobile platform that lets you style with CSS? (Serious question - I'm all web dev and don't know jack about mobile.)
It does not really matter. I think that this pen is just an interesting and inspiring experiment ;)
Nicely done, I like the colour selections and the overall concept. A suggestion: add a faded icon for the weather type happening in sections that don't currently have focussed. You have the space to do it, and it allows the interface to convey more information at a glance.