The average price for self-serve regular gas on Friday was down 4.5 cents to $2.89 a gallon, according to the Lundberg Survey of 7,000 gas stations across the country.
The American Automobile Association's Fuel Gauge Report Web site reported the national average Monday morning for regular gasoline as $2.84, down about a penny in the last month.
"These slight declines in prices were in the cards, as our refining capacity was coming back up from work projects and from hurricane damage of last year and from high imports of gasoline," Trilby Lunderg told CBS Radio News.
The break is nice, says Lundberg, but not when compared to last year.
"In the past seven weeks, gasoline prices are down about 6 cents. They peaked back in early May. But the price had gone up about 77 cents since late last year," she said.
The average mid-grade price was $2.99 a gallon while premium ran $3.09.
Charleston, S.C., had the lowest average price of gas in the U.S., selling at $2.61 a gallon. The highest average pump price, at $3.26 per gallon, was in Honolulu.
Lundberg said there are two reasons why the price decline was so slight.
"High crude oil prices and also recent ethanol prices. Petroleum refiners are required to buy minimal volumes of ethanol from ethanol refiners, and with the import tariff on ethanol, the supply of ethanol has been very tight," she said.
Prices of those (crude oil and ethanol) are not likely to crash any time soon. Therefore, here we are in the summer driving season, demand is flat but not shrinking. I expect that gasoline prices will neither rise nor fall to a great degree."