Gas prices jump 18 cents

(CNN) -- Gas prices jumped more than 18 cents over the past two weeks to a national average of $2.79 a gallon of self-serve regular, a national survey said Sunday.

That marks a rise of 60 cents since late January, said Trilby Lundberg, publisher of the "Lundberg Survey," which tallies prices every two to three weeks at about 5,000 gas stations.

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The current price is about 12 cents higher than it was a year ago, but still 24 cents lower than the record high set last August, she said. The latest surveys were carried out April 6 and March 23.

Lundberg attributed the price increases to problems at several refineries that cut gasoline production at a time of rising demand. For example, Valero Energy Corp. (Charts), the nation's largest independent refiner, shut its refinery in McKee, Texas, after a fire on Feb. 16. Though company officials are predicting a partial return to production within days, a full resumption is not expected until late in the year, she said. (See correction).

And the hemisphere's second-largest refinery - the Hovensa Refinery on the Island of St. Croix, the Virgin Islands - has shut for 10 days of maintenance, she said.

Lundberg said OPEC's million-barrel-a-day cut in production is also helping keep crude prices strong.

The cuts came as demand for gasoline was high, driven by a strong economy and the extra hour of daylight provided by this year's early arrival of Daylight Saving Time, she said.

Iran's release of 15 British sailors and marines resulted in a dip in prices, but "had no huge effect," Lundberg said.

Drivers in Charleston, S.C., paid the least, at $2.54 a gallon of self-serve regular; drivers in San Francisco paid the most, at $3.30.

Here are some other prices from around the country:

Salt Lake City: $2.58

Atlanta: $2.60

Houston: $2.64

Boston: $2.70

Pittsburgh, Pa.: $2.71

Cleveland: $2.77

Indianapolis: $2.83

Chicago: $2.86

Portland, Ore.: $2.95

Saint Louis: $2.69

(Correction: An earlier version of this story incorrectly stated that Valero's McKee, Texas, refinery was the nation's largest. CNNMoney regrets the error. Return to story).

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