http://www.wrh.noaa.gov/total_foreca...lon=-121.87875

this link from the national weather service is what I use.. I hope it works.. if it doesn't just go to
http://www.wrh.noaa.gov
and type in the city and state..
40% chance of rain on Saturday..

"Probability of measurable precipitation 40 percent" means 40% chance of rain..