The average price of a gallon of regular-grade gasoline dropped 7 cents nationally over the past two weeks to $2.54.
Industry analyst Trilby Lundberg of the Lundberg Survey said Sunday that the spike comes despite a jump in oil prices.
The current gas price is 34 cents above where it was a year ago. Gas in San Francisco was the highest in the contiguous United States at an average of $3.26 a gallon.
The lowest was in Tulsa, Oklahoma, at $2.18 a gallon.
The U.S. average diesel price is $2.88, holding steady from two weeks ago.