For the first time in months, most Californians are shelling out more than $4 for a gallon of regular gasoline. And with the busy summer driving season ahead, prices are likely to move even higher, fuel analysts said.

It's a rite of spring as predictable as warmer weather or blooming flowers: Gasoline prices are edging up.

A gallon of regular gasoline Thursday cost an average of $3.99 in the Golden State, the highest since September 2013, according to the AAA Daily Fuel Gauge report. In Los Angeles, gas stations are charging an average of $4.06 a gallon.

Prices typically start creeping north in spring as refineries begin producing a more expensive blend of summer gasoline, which takes longer to make and requires pricier additives as a pollution-fighting measure. As refineries look to offload their winter fuels, the supply of gas around the country is squeezed temporarily.

The switch often hits Californians earlier than residents in other parts of the country because of the state's strict standards for cleaner-burning fuel.

"The rise in gas prices this time of year comes around like clockwork," said Gregg Laskoski, senior petroleum analyst at GasBuddy.com, a fuel price tracking website.

In California, gas prices could remain at $4 a gallon or higher through much of the summer, when demand rises as people hit the road for vacations, experts said.

"If we see prices peak in April, they could still remain fairly high through much of the summer months," Laskoski said. "And we typically don't see a significant reduction until we have Labor Day behind us."

Luis Sanchez, 22, plans to cut down on nights out drinking with friends if prices at the pump keep climbing. The Santa Monica College student, who works part time as a deliveryman for a catering company, said his budget can't handle expensive gasoline.

"That could be food money," the West Los Angeles resident said. "I pay $50 a week already for gas. I just don't have the money to pay more."

So far this year, gas stations are charging a little less compared with the same time in 2013. The U.S. average Thursday was $3.54 a gallon, about 11 cents less than a year earlier. Californians are paying 6 cents less per gallon of regular gas.

Analysts say prices could inch up in coming months, but many don't expect any huge leaps. But fuel costs could become more volatile if turmoil erupts overseas in regions such as Russia and the Middle East, which could cause oil prices to surge, or if gasoline supply disruptions occur in the U.S.

Last summer, the threat of U.S. military intervention in Syria nudged up the cost of crude oil and retail gasoline for a bit. In 2012, power outages at a few California refineries helped contribute to record-breaking prices.

"Barring some unforeseen refinery shutdown or physical impairment, gas prices might go up a little more, it might go down a little," said Bernard Weinstein, associate director of Southern Methodist University's Maguire Energy Institute.

Booming domestic oil production and more fuel-efficient cars will help keep gas prices relatively stable in the U.S., analysts said. Advances in technologies such as hydraulic fracturing and horizontal drilling have unlocked previously inaccessible stores of oil.

By 2015, the U.S. is forecast to surpass Saudi Arabia and Russia as the world's top oil producer and move closer to energy independence in the next 20 years, according to the International Energy Agency.

That day can't come soon enough for Rod Kuzy. A representative for a cleaning company, Kuzy, 32, is often on the road for work. He said he is thinking about selling his Porsche Boxster and buying a car from Tesla Motors instead.

"I really like to drive," Kuzy said. "I'm concerned enough to start saving for an electric car."

shan.li@latimes.com

Twitter: @ByShanLi