My rainfall database project is working like a charm lately. It harvests the data from the web every day and stores it in a database. So far, I've got a week's worth of percent-of-normal data. Here's Modesto's.
Modesto 2014, percent of normal rainfall
It looks like what you'd expect when there's been no rain, a steady, monotonic decrease. Not very exciting. If we could only get some rain ...