The combined waters of fourteen tributaries of the Sacramento and San Joaquin rivers surge through the Carquinez Strait, past Benicia State Recreation Area, and west into San Pablo Bay on their way to the Pacific Ocean. Over the past 150 years, these waters have carried silt and clay from the hydraulic gold mines and timber logging sites of the Sierra and deposited the particles where fresh water meets salt water at Southampton Bay. The mudflat and marsh make up most of the recreation area, providing habitat for some unusual and endangered species. Benicia State Recreation Area covers 720 acres of marsh, grassy hillsides and rocky beaches along the narrowest portion of the Carquinez Strait. It is a day-use area that offers a quiet, breezy refuge from urban bustle and great views of the bay. Cyclists, runners, walkers, equestrians, and roller skaters enjoy the park's 2 miles of road and bike paths. Picnicking, bird watching and fishing are also attractions. The marshland area on Dillon's Point is a particularly favorite place for fishing. The climate is generally windy and cool year-round, with frequent fog. Temperatures range from 40 to 101 degrees, with average rainfall of 3 inches during winter months. The weather can be changeable; layered clothing is recommended. Dogs must be on leashes at all times.