From CNN:
WASHINGTON (Reuters) -- As the U.S. summer vacation season winds down, Americans face a surge in gasoline prices, the government warned on Wednesday.
Pump prices have increased 5.5 cents a gallon nationally over the last two weeks, the Energy Information Administration said in its weekly review of the oil market.
"It's possible that we may be in the midst of another late-summer surge (in gasoline prices)" said the agency, which is the Energy Department's analytical arm.
Higher gasoline prices pinch the pocketbooks of consumers and create a drag on the U.S. economy.
EIA said this year's gasoline market is following a pattern seen in 2000 and 2001, when there was a large gasoline price increase in the spring or early summer followed by a substantial price decline throughout the heart of the summer season, only to see prices rise again in late summer.
In 2000, the national price for regular gasoline rose by 11.4 cents per gallon during the four-week period from August 14 to September 11, and in 2001, prices rose by 16.9 cents per gallon between August 6 and September 3.
"Even if spot (wholesale) gasoline prices don't rise substantially from where they were last week...further increases in retail prices may occur, with increases in August possibly approaching those seen in the late summers of 2000 and 2001," EIA said.
The average retail price for regular unleaded gasoline increased this week for the fifth time in six weeks to $1.57 a gallon, the highest level since late April, the agency said.
Helping push gasoline prices up over the last few weeks is a rise in motor fuel demand and a higher crude oil cost that has hovered around $31 a barrel. The price of oil accounts for about 40 percent of the cost of gasoline.
Also, gasoline inventories are below normal. EIA reported on Wednesday that U.S. gasoline stocks stood at 198 million barrels, down 3.7 million barrels from the prior week and the lowest level in almost nine months.
EIA said higher gasoline prices would be needed to encourage refiners to process expensive crude oil into motor fuel, and more gasoline supplies will ultimately lead to lower pump prices.
"But this may not occur until after the end of the summer season," the agency said.