There are three distinct climactic gradients in northwest California.  First, there is a north-to-south trend of decreasing winter precipitation and warmer summer temperatures. Second, there is a west to east trend away from cooler and moister summer temperatures to a warmer, drier environment. Third, a montane gradient is expressed in which temperature decreases and precipitation increases with elevation. While in California’s Mediterranean climate it is difficult to calculate an “average” level of precipitation, as yearly fluctuations are common, northwest California offers more year-to-year stabilit than any other place in the state.