Nice concept, going to leave it on the phone with the other weather apps and see if I use it.
I guess you tried having just one clock and showing just the coming 12 hours? I'd think they might be even more intuitive for a first display because for a "glance at the upcoming weather" app I personally don't care much for the past weather :-)
Anyways I love apps which does only one thing well, bonus points for being under 1 MB. another favourite weather app is Sataa[1] (means rain in Finnish), which just shows the last hour of radar images for Finland.