Some analysts said the decline was a brief reprieve in the early weeks of what was expected to be a more-severe-than-normal Atlantic hurricane season.
Earlier in the year, the markets overreacted to supply problems and "got sloppy drunk on the prices," said Tom Kloza, chief oil analyst for Oil Price Information Service in Wall, N.J.
Kloza predicted that gasoline prices would be lower during the Fourth of July holiday than they were over Memorial Day weekend, adding: "This is a little bit of sobering up that we needed."
The average price of a gallon of self-serve regular gasoline fell 5.4 cents to $3.32 in California, according to the Energy Department's weekly survey of service stations around the nation.
That was 9.5 cents above the year-earlier price.
Several stations around the state were selling gasoline for less than $3 a gallon, including the Valero pumps at the AAA Auto Spa car wash in Fountain Valley, where it was going for $2.99 a gallon.
Nationally, the average dropped 8.1 cents to $3.076 a gallon, which was still 17 cents higher than during the same week in 2006.