Gas prices are on the rise, just in time for the holiday travel season.

According to the latest Trilby Lundberg survey, the average cost of regular has risen nearly 8 cents a gallon to $2.99.

San Francisco residents are paying the highest in the country at $3.29 a gallon. The lowest recorded price is in Denver, Colo., at $2.68.

"The retail rise would have exceeded a 10-cent rise if it wasn't for oil's slippage of $1.17 a barrel, which equates to nearly 3 cents a gallon equivalent," Lundberg said in a telephone interview with Bloomberg News.

The current price of retail gasoline is 39.16 cents above the year-ago price of $2.59 on Dec. 18, 2009, Lundberg said.

"It's a wide differential and the gain comes from crude oil price increases in late November and early December," she said.

Whether gasoline climbs to $3 a gallon by the end of the year depends on the "fluctuation in crude prices," which are "driving the price of gasoline more than usual," she said.

"There aren't other issues; we have a surplus of gasoline, a surplus of refining capacity and high unemployment," she said. 

The price covers the two-week period that ended Dec. 17 and is derived from data provided by 2,500 filling stations nationwide to Lundberg, an independent gasoline analyst in Camarillo, Calif.