Eyeing the Royal Farms sign advertising a gallon of premium gas for $3.99, Taryn Gross-Ojekwe's jaw fell open.
"When it is going to cease?" she said of the price, which has climbed steadily over the past few weeks. "Just within the last few days, it was $3.79."
As a freelance upholsterer, the Baltimore resident doesn't have a big enough income to brush off a quarter increase per gallon. The Nissan Sentra she parked at the pump on Russell Street on Monday afternoon now consumes about $60 at each fill-up.
Fortunately for Gross-Ojekwe and everyone else with a car, gasoline prices are expected to level off in the coming weeks, experts say.
Over the past seven weeks, the average price of a gallon of unleaded gasoline in the Mid-Atlantic region has increased more than 30 cents, from $3.72 per gallon on Aug. 6 to $4.04 on Monday, according to a survey by the U.S. Energy Information Administration.
Diesel prices, a major factor in the cost of shipping goods, have increased by about the same amount. The average price for a gallon of diesel is now $4.20, according to government estimates based on prices at stations from New York to Maryland.
"It's very rare to see a jump in September," said Ragina Averella, public and government affairs manager for AAA MidAtlantic. "Typically, we begin to see gas prices stabilize and actually fall through mid-September."
If another hurricane hits the Gulf of Mexcio or if the Middle East unrest worsens or flashes into a larger conflict, Marylanders may be forced to keep changing their spending habits to accommodate even higher prices.
Prices usually drop in the fall as people cut back on driving, Averella said. If people are driving less, demand for fuel decreases and prices at the pump drop, she said.
In terms of declining demand, this autumn is no exception. What made prices go up are complications on the other side of the supply-demand equation.
Crude oil prices, which translate to higher retail gas prices, have remained high this month because of Hurricane Isaac blowing across the Gulf of Mexico in August. The storm forced many oil wells to shut down for safety reasons, according to AAA.
Then, AAA said, several factors last week combined to push retail gas prices up even more: unrest in the Middle East over a YouTube video that was offensive to Muslims; the Federal Reserve announced another economic stimulus; and a German high court decision caused the value of the dollar to drop.
"It's not an easy thing, trying to predict what gas prices will do, because so many factors are involved," Averella said. "We expect prices will go down, but we always have to be mindful of ongoing geopolitical events, not to mention the fact that we are still in hurricane season."
U.S. consumers usually see the lowest gas prices of the year from October through December, said Gregg Laskoski, a senior petroleum analyst with GasBuddy.com, which tracks gasoline prices.
"There's no question that a lot of people are very nervous that here we are, two weeks after Labor Day, and nationally, prices are still this high," Laskoski said.
He agreed with Avarella's assessment, that weather and international factors have pushed prices up during a period when they normally go down. "This year is a little bit different than what we've seen in past years, partially because of Isaac and partially because of what we saw last week" in the Middle East, he said.
Those unexpected events may be counterbalanced in the coming weeks, Laskoski said, by one that is like clockwork: refineries' annual switch from producing a summer gasoline blend to a winter mix, he said.
Government regulation "creates this roller-coaster effect on gasoline prices" each spring and fall when producers change their formulas, he said.
Summer-blend gasoline contains additives that reduce smog, he said. The federal government mandates the additives' use during the summer months, when metropolitan areas are more affected by air pollution. The period during which retailers must sell the summer mix ended Saturday, according to AAA.