SAN FRANCISCO, Calif. — If you think Southern California gas prices are high now, they are about to get even worse.

You may want to fill up your gas tank this weekend before prices go up on Monday. California will have the highest gas prices in the nation when new gas tax kicks in July 1.

California's gas tax increases by nearly 6 cents per gallon to more than 60 cents per gallon, making it the highest in the nation.

The increase is expected to generate nearly $54 billion in revenue over a decade.

Last November, California voters rejected a statewide proposition to repeal the gas tax increase.