The year-end fires sweeping Southern California this week have raised a worrisome question: Where is the rain?The rainy season typically starts in October and lasts through April, with the heaviest rain coming from December through March. Precipitation has been at or above-normal in Northern California, but there has been little rain in the south.Since Oct. 1 just 2.3 inches have fallen in Los Angeles, or 5 percent of average. In San Diego, it’s 1.5 inches, or 1 percent of average, according to the California Department of Water Resources.