Pleasant Hill is a city in Contra Costa County, California, United States, in the East Bay of the San Francisco Bay Area. The population was 33,152 at the 2010 census. It was incorporated in 1961. Pleasant Hill is the home of College Park High School, Diablo Valley College, John F Kennedy University, the Pleasant Hill Library and administration offices for the Contra Costa County Library system, and the Pleasant Hill Recreation & Park District.GeographyAccording to the United States Census Bureau, the city has a total area of 7.1sqmi. Pleasant Hill has a varied landscape with some valleys and rolling hills. In undisturbed wilderness, oak woodlands and mixed woods can be found. It is located in the central East San Francisco Bay.ClimateThis region has warm and dry summers, with no average monthly temperatures above 71F According to the Köppen Climate Classification system, Pleasant Hill has a warm-summer Mediterranean climate, abbreviated "Csb" on climate maps. Winter daytime temperatures tend to be in the fifties and sixties, and summers range in the high seventies to upper eighties, occasionally reaching the low nineties. On very rare occasions, the temperatures can reach the one hundred degree range during extreme heat waves. Freezing in winter is rare, but it does happen. Summer fog is occasional but winter fog is very common.