Motorists at some locations in California are now paying $5.00 and up for a gallon of gas -- among the highest recent pump prices in the state and the country.

The seriously elevated prices means California motorists still pay the most for gas in the U.S. with prices some $1.54 higher than the national average. Experts noted California gas prices haven't been this high since May 2014.

A few and scattered gas stations in the state, including those in the Los Angeles area, are now charging at least $5 a gallon. A Mobil station in West L.A. advertised gasoline for $5.29 per gallon of regular unleaded Tuesday morning. A gallon of supreme at this station cost $5.69.

Mono County located east of the Sierra Nevada between Yosemite National Park and Nevada has the most expensive gasoline prices in the state on average. The average stood at an eye-popping $4.93 as of Tuesday, according to the American Automobile Association (AAA).

The last time Californians saw pump prices this high was some five years ago.

On Tuesday, a gallon of regular unleaded gasoline at the pump went for $4.19 a gallon on average throughout the state. This price follows a $0.16 increase in gas prices statewide, the biggest weekly increase in the U.S. over a period that ended Monday, according to AAA.

The race to $5 a gallon continues in other parts of the Golden State.

On average, L.A. County drivers are paying $4.26 a gallon. The average is $4.25 in Ventura County; $4.22 in Orange County; while it stands at close to $4.20 in Riverside and San Bernardino counties.

The U.S. Energy Information Administration (EIA) said the highest weekly average price of gas in the U.S. was reached during the week of July 7, 2008 at $4.11 per gallon for regular.

Experts said refinery outages along the West Coast are a major factor for the recent surge in pump prices. These unexpected events crimped California's fuel supply.

“All regions are seeing planned and unplanned refinery maintenance, but it is only the West Coast that is really seeing gasoline stocks tighten and gas prices increase,” said Jeanette Casselano, AAA spokeswoman in a statement.

The good news is refineries are working non-stop to resume production capacity. Gas prices in California will start to decrease, argues Patrick DeHaan, head of petroleum analysis at GasBuddy.com.

"Significant relief will be coming starting very soon," said DeHaan Tuesday.

He noted gas prices might fall near $0.50 a gallon by Thanksgiving.

Based in Boston, GasBuddy is a tech company operating apps and websites based on finding real-time fuel prices at more than 140,000 gas stations in the U.S., Canada and Australia.

Gas prices The average price of gas in the U.S. has decreased by two cents a gallon to $2.91 over a two-week span. A gasoline station attendant is pictured pumping diesel into a car at a filling station on Mar. 23, 2010 in Berlin, Germany. Photo: Sean Gallup/Getty Images