California drivers already dealing with the nation’s highest gas prices are are bracing for another painful jump at the pump this summer. Weston Hancock/SOPA Images/ShutterstockThe average price for a gallon of regular gas in California has increased by 10 cents over the past week, according to gas price tracking websites. The global supply crunch may be driving prices higher, but California drivers are already starting from a far more expensive baseline. California gas drivers are paying a lot. The counties with the highest gas prices include:Mono County — $6.83 per gallon of regular gas— $6.83 per gallon of regular gas Inyo County — $6.14— $6.14 Sierra County — $6.10— $6.10 San Luis Obispo County — $5.92— $5.92 Humboldt County — $5.90The cheapest counties include:Sutter County — $5.30 per gallon of regular gas— $5.30 per gallon of regular gas Tehama County — $5.38— $5.38 Yuba County — $5.38— $5.38 Butte County — $5.45In the major metro areas, more of Northern California is paying higher than Southern California.