The average price of a gallon of self-serve regular gasoline in Riverside County rose Saturday to its highest amount since July 22, 2015, increasing a half-cent to $4.174.
The average price has increased 59.2 cents over the past 21 days, including four-tenths of a cent Saturday, according to figures from the AAA and Oil Price Information Service. It is 17.9 cents more than one week ago, 58 cents higher than one month ago and 40.1 cents greater than one year ago.
The 2015 figure included stations in San Bernardino County.
Gas prices began increasing rapidly last month after Saudi Arabia oil production facilities were attacked, and the increases sharpened after three Los Angeles-area refineries slowed or halted production due to maintenance issues and no imported gasoline was available to make up for the shortfall, according to Jeffrey Spring, the Automobile Club of Southern California's corporate communications manager.
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Local refineries had already cut back production of summer blend gasoline in anticipation of switching to selling the winter blend beginning Nov. 1, creating even more of a shortage.
"The good news is that Los Angeles wholesale gasoline prices have dropped sharply in the last two days after refiners began selling off gasoline and there are indications that refinery production problems are ending," Spring said.
"However, drivers are not likely to see much relief at the pump quickly, since retail prices have shot up by over 50 cents and are typically much slower to decline after a sharp increase."