The climate of the Russian River watershed can be described as “Mediterranean,” meaning that little rainfall occurs during the hot summer months, and that winters are mild and wet. The summer drought in the Russian River watershed usually begins in May and lasts through September. On average, less than 5% of the annual precipitation occurs during these five months. The rains begin to fall in October and November and occur off and on through winter, producing an average of up to 70 inches per year of rain along the coast, and 40 inches per year inland. Due to the influence of the Pacific Ocean, temperatures are rarely low enough to freeze for prolonged periods, and snow only occurs briefly at high elevations. Precipitation is highly variable from one year to the next. Although the average precipitation in an inland valley may be 40 inches, the range over several decades may be from as little as 15 inches in a dry year to as much as 85 inches in a wet year.