Diesel Hits Record $5.85 a Gallon Nationally as Iran War Disrupts Fuel Markets

The average price of diesel in the United States climbed to an all-time high of $5.85 a gallon on Friday, according to AAA, capping a months-long surge driven by a grinding conflict with Iran that has upended global energy supply chains.

The milestone represents a roughly 56% increase over the $3.76 national average recorded before the U.S. and Israel launched their war against Iran in late February. Since then, crude oil prices have ballooned, with Brent crude — the international benchmark — trading above $95 a barrel on Friday, up from around $70 before hostilities began. Much of the disruption traces to the Strait of Hormuz, the narrow waterway through which the majority of the world's tanker traffic passes, which has been effectively bottlenecked by the fighting.

After dipping earlier in the summer amid hopes for a peace deal, prices have accelerated once again as combat between the two countries has reignited.

Maine Drivers Feeling the Pinch

The impact is plainly visible at the pump in Maine. According to AAA, the average cost of regular gasoline in the state stood at $4.18 per gallon on Friday, compared to $3.14 a year earlier. Diesel has climbed even more sharply — from $3.90 per gallon last September to $5.87 as of Friday, nearly matching the national record.

The pain at the pump, however, may only be the beginning.

From the Pump to the Shopping Cart

Diesel fuels the trucks, trains, and freight networks that move nearly every category of goods Americans buy. That makes its price a powerful lever on the cost of living as a whole. Several major shippers — including Amazon, UPS, FedEx, and the U.S. Postal Service — have already tacked fuel surcharges onto some packages since the war began, and retailers have begun passing higher transportation costs to online shoppers.

The grocery aisle is where the strain is showing up first. Fuel accounts for roughly 15% to 30% of the total cost of food, according to the Independent Grocers Alliance, a network of 7,500 global supermarkets. Perishable items that must be refrigerated in transit — meat, seafood, produce — tend to see price increases before shelf-stable goods. In July, overall U.S. grocery prices were up 2.7% compared to a year earlier, but seafood rose 7% and fresh fruit climbed 4.9%.

David Ortega, a professor of food economics and policy at Michigan State University, noted that other factors can complicate the picture — a cyclospora outbreak, for example, pushed down demand and prices for lettuce in July despite higher transportation costs.

The full effect on consumers may still be ahead. "Early on, much of the cost increase gets absorbed along the supply chain through existing freight contracts and retailer margins," Ortega said. "But as contracts reprice and fuel surcharges take hold, more of that cost makes its way to the grocery store."

Gasoline Climbing, Too

Regular gasoline has risen alongside diesel, though at a slower pace. The national average of $4.15 a gallon is up 39% from the $2.98 recorded before the Iran war, though still well short of the nearly $5.02 peak reached in June 2022 following Russia's invasion of Ukraine. AAA noted that gas has never previously been priced above $4 a gallon on Labor Day.

Ajesh Kapoor, CEO of trucking technology firm SemiCab, said the transportation industry can adapt to rising diesel costs — but only up to a point. "Diesel price has a very, very direct impact on everything that moves on pretty much any mode," he said.

The reach of diesel extends well beyond highways. Public transit buses and passenger trains often run on the fuel. Diesel generators supply backup and emergency power across the country and serve as the primary electricity source in some remote corners of the world.

Global Pressure Points

The consequences of the fuel shock are being felt unevenly around the world, hitting countries that depend most heavily on Middle Eastern imports the hardest. According to Global Petrol Prices, diesel in Nigeria has surged 90% since late February, followed by nearly 87% in Indonesia and 77% in Lebanon. By contrast, Hong Kong — where prices were already among the world's highest — saw diesel jump more than 25% during the war to an average of $17.73 a gallon.

Speaking at a weekly briefing with Lloyd's List Intelligence, Neil Atkinson, an energy analyst and senior fellow at the National Center for Energy Analytics, warned that global refining capacity is being strained as prices rise and physical stocks dwindle. "This cannot go on forever," he said.

Historical Context — and Political Stakes

Diesel last approached record territory in June 2022, when it averaged nearly $5.82 a gallon in the wake of sanctions on Russia following its invasion of Ukraine. Adjusted for inflation, however, this week's nominal record is not yet the highest ever. Diesel peaked at roughly $4.74 a gallon ahead of the 2008 financial crisis, the equivalent of about $7.20 in today's dollars, and the 2022 high would equal roughly $6.56 in 2026.

Still, the current spike lands amid an already strained political environment. AP-NORC polling this summer found that two out of three U.S. adults disapprove of President Donald Trump's handling of the economy, with the Iran war's fallout adding to a list of voter concerns ahead of November's midterm elections.

Staff Writer Drew Johnson and AP Writers Dee-Ann Durbin in Detroit, Mae Anderson in New York, and Bill Barrow in Atlanta contributed to this report.