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About Lake County

Clear Lake is at the heart of Lake County, and is the largest natural lake in California and possibly the oldest lake in North America with an estimated age of 2.5 million years. Lake County boasts the cleanest air in the state of California.

Location & Size

Lake County is in Northern California, north of the San Francisco Bay Area. It is slightly inland from the Pacific Ocean. It is bordered by Napa, Sonoma, Mendocino, Glenn, Colusa, and Yolo counties. Lake County covers an area of 1,327 square miles.

  • 100 miles/2 hours on Interstate 5 from Sacramento
  • under 100 miles on Highway 29 from Alameda, Contra Costa, Solano and Napa counties
  • 110 miles on Highway 101 from San Francisco

Weather & Climate

Lake County has a Mediterranean-style climate with four distinct seasons, including a lush and vibrant spring, a long dry and warm summer, an autumn with warm days and cool nights, and a wet, mild winter with occasional snow on the mountaintops. Lake County rarely experiences coastal or valley fog, which translates into lots of sunshine – approximately 265 days of clear or partly clear skies on average.

Average Temperatures Highs Lows
January-March 60º 32º
April-June 80º 48º
July-September 95º 57º
October-December 65º 44º

Average Annual Rainfall
Clear Lake Basin 25 inches
Middletown area 45 inches
Cobb Mountain 60 inches

Clear Lake Average Water Temperature
December 48º
March 53º
June 66º
August 75º

Natural Wonders

Nature’s wonders abound in Lake County. Clear Lake is the largest natural lake in the state of California. The Geysers is the largest geothermal field complex in the world. “Lake County diamonds” are there for the picking. Mt. Konocti, formed by volcanic eruptions, can be seen from anywhere on the lake. Lake County is home to Tule Elk, more than 150 bird species, the Clear Lake Hitch, a native fish found only in Clear Lake, and native trees – all of which make Lake County a natural wonderland.

Major Industries

The local economy is based primarily on agriculture, tourism, and the geothermal power industry. Lake County is an ultra-premium winegrape-growing area and also is famous for its pears and walnuts.

We encourage you to come, visit, explore, and make vacation memories that will last a lifetime!

The Official Tourism Site for Lake County, California © Lake County Marketing and Economic Development Program. All rights reserved. | FOR VISITOR INFORMATION, please call 1-800-LAKESIDE.
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