U.S. diesel prices have climbed to their highest level on record, driven by six months of war with Iran and persistent disruptions to global fuel supplies. The surge could ripple through transportation, agriculture and food prices, adding new inflationary pressure ahead of the November midterm elections.
U.S. diesel prices reach a new record
On Friday, Sept. 4, U.S. diesel prices hit a new record, climbing to around $5.85 a gallon for the first time, as the six-month war with Iran and continued disruptions to fuel flows put pressure on supplies. Higher diesel prices inevitably translate into higher transportation costs for a wide range of everyday goods.
The national average for diesel reached $5.820 a gallon, according to data from fuel-price tracking service GasBuddy. That surpassed the previous record of $5.819 a gallon, set on June 17, 2022, several months after Russia invaded Ukraine.
Average diesel prices have remained above $5 a gallon since at least July 15. Patrick De Haan, head of petroleum analysis at GasBuddy, wrote on X that 2026 could go down as the most expensive year for diesel in U.S. history.
U.S. diesel prices and the war with Iran
Diesel prices have risen 55% in the United States since the U.S.-Israeli war with Iran began. Before the conflict, about 900,000 barrels a day of diesel and 350,000 barrels a day of jet fuel moved through the Persian Gulf, representing roughly 10% and 20%, respectively, of global seaborne supplies, according to data from commodity-tracking firm Vortexa.
The escalation of the war involving the United States, Israel and Iran, which began in late February 2026, has sent fuel prices sharply higher worldwide, once again underscoring the vulnerability of global energy markets to geopolitical shocks.
Brent crude prices climbed to multiyear highs between late April and early May, rising above $100 a barrel. In the United States, gasoline prices have increased by about 45%, while diesel prices have risen by just over 48% since the start of the conflict.
Diesel prices could rise further in the coming months
Analysts have warned that diesel prices could climb further in the months ahead. Farmers harvesting crops across the Northern Hemisphere, along with those preparing for planting in the Southern Hemisphere, are expected to boost diesel consumption. Demand for heating oil also typically increases ahead of the winter season.
Higher diesel prices can reverberate throughout the economy because the fuel is widely used in trucking, agriculture and industry. Rising transportation and production costs can ultimately push up prices for food and other consumer goods.
The diesel price surge also coincided with Labor Day weekend, one of the busiest travel periods of the year in the United States. Prices are facing additional pressure from attacks on Persian Gulf refineries and Ukrainian drone strikes targeting refineries in Russia.
Russia, which accounted for more than 10% of global diesel exports just last year, is now importing both diesel and gasoline and has banned fuel exports.
Trump’s energy policies and the midterm elections
U.S. refineries, meanwhile, are operating near the limits of their capacity. Some have postponed maintenance work, Politico reported, increasing the risk of equipment failures that could drive prices even higher.
The new diesel price record could add to inflationary pressures, potentially complicating Republicans’ efforts to retain control of Congress in November’s midterm elections.
