Santa Barbara gas prices have experienced one of their biggest weekly jumps, according to the Auto Club of Southern California.

The area’s average price of a gallon of unleaded gasoline was $4.273 on Thursday, up 21.9 cents from last week, according to GasBuddy.com. That price ticked up 39.1 cents in the past two weeks and 49.2 cents in the past month. Thursday’s average was 65.1 cents higher year-to-date.

The national average of $3.595 increased 10 cents from last week and 24.8 cents since last month.

Auto Club spokeswoman Marie Montgomery said that while it’s normal for gas prices to climb in the spring as motorists drive more and refineries close for maintenance, prices don’t usually increase this early. Refinery closures, Iran threatening to halt oil exports to Britain and France, and increasing crude oil prices are points of concern.

“We heard that after the Washington refinery caught fire wholesale prices went up by 35 cents in one day,” Montgomery said.

Also, she added, a lot of gas has been purchased on the spot market when usually California makes most of its own supply. If California has to go to outside sources for its gas, prices will increase.

The average price for a barrel of crude oil was $106.270 on Thursday, up $7.97 from two weeks ago.

“With oil right now, a lot of it comes from the Middle East and with Iran and civil unrest throughout the region,” Mission Wealth Management co-founder Brad Stark said. “People are concerned that supply could be disrupted in the future. “

But prices can drop as easily as they’ve spiked, Stark added.

“People need to understand that commodity prices are extremely volatile and subject to the forward markets predicting the future price with willing buyers and sellers coming together on an agreed upon price for a future deliverable,” he said.

Santa Barbara drivers can find gas priced at $4.09 at the USA Gasoline stations at 636 W. Carrillo St., 340 W. Carrillo St. and 8 S. Milpas St. as well as the Thrifty at 4069 State St. The next cheapest price of $4.15 can be found at the World station at 5960 Calle Real, the 76 at 2837 De la Vina St. and the 76 at 1800 State St. The USA Gasoline at 340 W. Carrillo St. has the least expensive diesel fuel at $4.09.

The most expensive stations are the Shell at 55 N. Fairview Ave. at $4.69 and the 76 at 42 N. Fairview Ave. at $4.65.

In terms of local impact, Montgomery said the most common ways people are cutting back on gas consumption are eating out less and not driving unnecessarily.

“That may impact the restaurant industry,” she said.

— Noozhawk business writer Alex Kacik can be reached at akacik@noozhawk.com. Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.