Orinda is a city in Contra Costa County, California, United States. The population was 17,643 at the 2010 census, and was estimated in 2012 to have increased to 18,342. Orinda was ranked 2nd most friendly town in America by Forbes Magazine. The town is located just east of the city of Berkeley and is home to many affluent suburban professionals who commute to downtown Oakland, San Francisco, and Walnut Creek. Orinda's location provides for a more rustic landscape, and Orinda's many parks and trails make it a destination for many Bay Area hikers and naturalists.
According to the United States Census Bureau, the city has a total area of 12.7 square miles, of which, 12.7 square miles of it is land and 0.015 square miles of it is water.
The area is characterized by a warm-summer Mediterranean climate with cool, rainy winters and hot, dry summers. It is located in the Chaparral biome. Because Orinda is located in a hilly area, microclimates often dominate temperature differences in short distances. The Oakland hills often times block the cool foggy conditions that can be seen in Oakland and the inner bay. In the summer, fog can spill over the Oakland hills cooling off the area. Heat waves from the inland areas can be felt much more in Orinda than in Oakland and the inner bay during the summer. In the winter, Orinda often times sees more precipitation than surrounding areas because of its higher elevation. Snowfall is rare but not unheard of. A dusting of snow may occur any given year because of the elevation. During stable conditions in the winter, mornings can be rather cold and frosty in downtown and lower lying areas while the higher hills surrounding the area may be several degrees warmer.