A nearly 10 percent price spike over the past month brought the price of a gallon of regular gas close to $4 in Santa Rosa on Tuesday, a trend attributed largely to rising crude oil prices.

Santa Rosa motorists paid an average of $3.94 a gallon Tuesday, up 38 cents since AAA Northern California's last report Jan. 8.

The GasBuddy.com website listed 22 local service stations with prices below that average on Tuesday, the lowest at $3.81 a gallon.

On Friday, the statewide average surpassed $4 a gallon, the first time since Nov. 3, the AAA said.

California's average price was $4.06 on Tuesday.

Eureka, Oakland, Pleasanton, San Francisco, San Mateo and South Lake Tahoe also were above $4.

Both the AAA and the U.S. Energy Department cited rising crude oil costs as a factor for the year-opening price surge.

Brent crude, a benchmark for imported oil prices, rose from $109 a barrel in mid-December to about $119 in early February.

That $10 increase equates to about 24 cents per gallon of gas, the government agency said.

Still, the agency's latest forecast predicted lower oil prices because of increased production by countries outside of the Organization of the Petroleum Exporting Countries.

Crude oil production in the U.S. is expected to grow 13 percent, to 7.25 million barrels a day this year.

As a result, the government said, gas should peak at an average $3.73 a gallon in May, 21 cents below last year's high of $3.94 in early April.

California prices are typically 20 to 40 cents a gallon higher than the national average.

Santa Rosa's all-time record price of $4.65 was set Oct. 9.

You can reach Staff Writer Guy Kovner at 521-5457or guy.kovner@pressdemocrat.com.