The average price of a gallon of self-serve regular gasoline in Los Angeles County topped $4 for the first time since May 24 on Saturday, recording the largest daily increase since July 15, 2015, 7.2 cents.
The average price has increased 12 consecutive days, rising 37 cents to $4.042, according to figures from the AAA and Oil Price Information Service.
It is 25.1 cents higher than one week ago, 47.2 cents higher than one month ago and 27.2 cents greater than one year ago.
The average price has risen 65.1 cents since the start of the year.
The Orange County average price topped $4 for the first time since May 20, with its largest daily increase since July 14, 2015, 8.1 cents.
The Orange County average price of $4.024 is 27.1 cents more than one week ago, 47.5 cents higher than one month ago and 29.4 cents greater than one year ago. It has risen 38.8 cents since Sept. 17 and has increased 67.5 cents since the start of the year.
The rising prices are the result of diminished supply primarily caused by unplanned maintenance issues at the Chevron and Marathon refineries in Los Angeles County and the absence of imported gasoline, according to Jeffrey Spring, the Automobile Club of Southern California's corporate communications manager.