Thanks so much for trying Sunmetrix. We do keep track of some of the variables you mentioned (e.g., cloudy days), however since the sensors we use are very far away (1/10th the distance to the Moon), it's not possible for us to monitor things like mud on a solar panel. The main point of using Sunmet...

Very cool project! We developed a software that uses satellite data to monitor solar panel installations ( http://sunmetrix.com/track-landing ). I wonder if our data may be of use to this effort.