Taking that affordable summer road trip, or just driving around town to do errands, might suddenly be a budget buster.
The national average for a gallon of regular unleaded gasoline hit $3.61 on Monday, according to AAA. That's up 14 cents from a week ago, and the largest price spike since February, said AAA spokesman Michael Green.
Analysts expect prices to climb further, edging up another 5 to 15 cents a gallon before the end of July.
"Crude oil prices are up 10 percent in the last three weeks, and gas prices have some catching up to do," said Patrick DeHaan, senior petroleum analyst for GasBuddy.com. "When oil prices are up, gasoline is bound to follow."
Several other factors have played a role. Crude prices have trended higher on news of minor production problems at several U.S.refineries, as well as continued violence in Egypt.
"That spooks the market," Green said. News on either issue could push prices higher, or lower if the news points to increased supply.
Prices aren't likely to settle before Labor Day, or even September.
"The 500-pound gorilla that's ready to walk in the door is the upcoming peak of hurricane season" in August, DeHaan said. After Hurricane Katrina damaged refineries in the Gulf of Mexico in 2005, spiking prices and stretching supply, major storms moving in that direction generate concerns. And that can edge crude prices up.
That said, drivers in most states won't see prices top $4 a gallon, Green said. (Just Alaska, California and Hawaii had prices surpassing that mark.)
Drivers can use a variety of strategies to cut their pain at the pump, though. The Department of Energy's FuelEconomy.gov recommends a number of approaches, including observing the speed limit (saving 7 to 14 percent) and clearing extra items from your vehicle (1 to 2 percent savings per 100 pounds).
But the best recourse, experts say, is to assess local prices before filling up.
"When prices are volatile, that can mean a wider gap between the cheapest and most expensive stations," said DeHaan. Drivers could save as much as 70 cents a gallon just by choosing the right station.
Apps like GasBuddy and AAA TripTik display local prices, helping drivers determine which local stations are cheapest. (Some sites and apps rely on users to submit new prices; check when a price was submitted before banking on it as the best savings.)
Pair that with the right payment method. Some gas stations offer savings of roughly 5 cents a gallon if you pay cash. Convenience store chain Cumberland Farms launched a payment app in January offering users discounts of 5 cents to 10 cents a gallon.
Plenty of credit cards also offer generous rewards on gas purchases, according to Odysseas Papadimitriou, chief executive of comparison site CardHub.com. Look for a general rewards card rather than one tied to a specific station. General cards are also less apt to cap rewards earned, making them more generous than station-specific cards when prices are rising, he said.
CardHub.com's top pick is the PenFed Platinum Rewards card, which offers 5 percent cash back when you buy gas. Cardholders must be members of the credit union but can sign up for as little as $15.
Supermarket loyalty programs could open up another avenue for savings. Although memberships in such programs haven fallen 1 percent since 2010, according to research firm Colloquy, chains have added more gas discounts connected to grocery purchases. In some cases, shoppers can earn discount vouchers for more than $1 a gallon on a single fill-up, based on something they would do anyway: buy groceries.
—By CNBC.com's Kelli B. Grant. Follow her on Twitter