San Diego County drivers are paying $6.08 per gallon for regular gasoline, among the highest prices in the nation. The war in Iran is driving the surge.

Diesel is even steeper. The county average stands at $8.02 per gallon, according to AAA data reported by the North County Daily Star on Wednesday, Sept. 16. California leads the nation in both gasoline and diesel prices, with statewide averages of $6.01 for gas and $8.21 for diesel. Gasoline is nearly 50 cents above second-place Washington.

At Carlsbad pumps, the costs are adding up. An Associated Press photograph taken Thursday, Sept. 10, showed Lawrence Allison putting $175 worth of diesel into his truck at a Carlsbad gas station, Reuters reported. That same day, the national average diesel price crossed $6 per gallon for the first time, according to GasBuddy.

Nationally, diesel has surged nearly 60% since the U.S. and Israel launched military strikes against Iran in late February, Reuters reported. Crude oil futures topped $100 per barrel in September for the first time since May, according to CNBC. U.S. diesel inventories sit 13% below their five-year average at 106.3 million barrels, according to the Energy Information Administration (EIA).

Bernard Yaros, lead U.S. economist at Oxford Economics, told Fox Business that diesel is the primary fuel powering the U.S. economy, especially in agriculture and freight. It runs the irrigation pumps, tractors and delivery trucks behind every trip to the grocery store, Yaros said.

For Carlsbad households, the numbers add up fast. Americans have collectively spent more than $100 billion in extra fuel costs since the Iran war began, amounting to more than $805 per U.S. household, according to a Brown University analysis cited by Gov. Gavin Newsom's office on Monday, Sept. 14. California households have paid an estimated $372 in extra fuel costs since the war began.

Patrick De Haan, head of petroleum analysis at GasBuddy, told the North County Daily Star that prices have "nowhere to go but up." He said the national diesel average could reach $6.58 per gallon within a week, matching the inflation-adjusted peak set in 2022.

A Saudi pipeline closure after a drone attack threatens to tighten supply further, KCRA reported. About 20% of global petroleum normally flows through the Strait of Hormuz, which Iran has controlled since the conflict began, according to the EIA. Repairs to the Saudi pipeline are estimated at three to five weeks.