Climatic Regions of the United States, Mediterranean
The Mediterranean climate of central and coastal California is characterized by dry summers and mild, rainy winters. The name was given to this climate because it is also found in areas bordering the Mediterranean Sea.
Summer temperatures range from 20° to 25° C (70° to 80° F), and winter temperatures are a mild 4° to 10° C (40° to 50° F). The average precipitation of 360 mm to 640 mm (14 in to 26 in) per year occurs during the cool winter season and contrasts sharply to the area's dry summer months. There is a complex variety of soils in this region, which vary greatly in moisture, temperature, slope, and elevation.
The Mediterranean climate pattern reverses the traditional growing seasons: Plants thrive in the wet winter and wither during the dry summer. In order to survive the dry summers, plants have developed deep taproots, thick bark, and leathery leaves to obtain and conserve moisture. These types of plants are called sclerophylls. Trees are relatively small, with branches close to the ground and gnarled trunks. Chaparral, a low-growing woody shrub, dominates the valleys and lower mountain slopes. Sclerophyll forests grow along the California Coast Ranges, where live oak and white oak dominate. Grassland occupies the open ground between the scattered oaks. Game birds include grouse, mourning doves, and quail. Deer, foxes, minks, wildcats, wolverines, and a few mountain sheep roam the mountain and forest areas.
To allow crops to grow during the summer months, large-scale irrigation projects have been constructed. Most irrigation occurs in the Great Valley of California, where the Central Valley Water Project provides water through a series of dams and aqueducts. Irrigation has transformed this area into a region of high productivity; the total value of farm products sold in California is higher than in any other state.
In the 1990s California with its numerous vineyards was the major wine producer in the nation. The climatic conditions and rich alluvial soils in valleys allow California farmers to grow more than 200 different crops, making the state one of the nation's leading agricultural producers. Dairy cows, livestock, and poultry also flourish.