After rising steadily since the start of 2012, local and national gasoline prices have finally begun to drop, a trend experts say could continue for the next several weeks.
In South Carolina, the average price per gallon of unleaded gasoline fell 6 cents in the past week, to $3.64.
That's the fifth-lowest average in the nation, according to GasBuddy, a Minnesota-based business that tracks gasoline prices at more than 140,000 stations in the U.S. and Canada.
Tom Crosby, vice president of communications for AAA Carolinas, said an unusually mild winter is partly responsible for the dip.
South Carolina's gasoline is supplied by refineries in the Gulf of Mexico that also produce an oil used in commercial and residential heating systems, he explained. Because demand for that oil subsided earlier than usual this spring -- by about two weeks, Crosby estimated -- the refineries completed their production ahead of schedule of a more expensive seasonal blend of gasoline that combats air pollution in the Northeast.
"That's a very good sign for keeping prices down," Crosby said. "There's a good chance they could continue declining for another five weeks," adding that the trend will likely end with a bump of a few cents per gallon during Memorial Day weekend.
South Carolina's relatively inexpensive gasoline is owed largely to its low fuel tax. At 35.2 cents per gallon -- about 20 cents less than the national average -- the tax is the fourth-lowest in the country, according to a report this month by the American Petroleum Institute.
Although gasoline at most Beaufort County stations is selling for between $3.70 and $3.80, according to GasBuddy, it's fallen 7 cents in the past week across the Upstate, where the average price is about $3.59.
Gregg Laskoski, a senior analyst at GasBuddy, called the recent dip a "significant decrease" during a time of year when prices generally rise.
He added that consistently high prices last year led the average American household to spend $4,100 on gasoline, a figure he said "might be the highest (average) of all time."
He attributed the recent trend primarily to Iran's compliance with the United Nations after it was threatened with sanctions because of its nuclear program. Iran is one of the world's leading crude-oil producers.
"That's something that has taken a lot of nervousness out of the financial markets," Laskoski said. "But if they withdraw (from negotiations), I can guarantee crude oil prices will escalate within the hour."
And he says that's not the only development that could drive local prices back up.
"We've been monitoring the monthly job reports, and the decrease in unemployment should result in an uptick in consumer demand," he said. Prices could rise to reflect that demand, as more people rely on gasoline to drive to their jobs.
According to a report released last week by the S.C. Department of Labor and Workforce, the statewide unemployment rate dropped in March for the eighth consecutive month.