Diesel prices in the United States have climbed to record territory, with GasBuddy reporting the national average above $6 a gallon and AAA listing diesel at $5.9773 on September 10. That is sharply higher than AAA’s year-ago average of $3.7060 and raises fresh concerns about transport costs, inflation and pressure on businesses that depend on heavy-duty fuel.
Oil shock
The latest oil shock has pushed fuel markets higher as geopolitical tensions disrupt energy flows and increase concerns about available supply. Brent crude settled at $107.63 a barrel on September 10, while West Texas Intermediate finished at $102.48. Crude prices remain a major driver of retail fuel costs, but diesel is also being affected by tight supplies of refined products.
Hormuz
The Strait of Hormuz remains a critical risk for global energy markets because disruptions along the route can quickly affect crude and refined fuel shipments. Recent conflict involving the United States, Israel and Iran has increased concern about tanker movements and supply reliability. Any prolonged disruption could keep diesel and other fuel prices elevated even if US refineries continue operating at high rates.
Refineries
Global refinery constraints are adding another layer of pressure. Damage and outages affecting Russian refining capacity have reduced available diesel supplies, while export restrictions from major producers have limited the amount of fuel reaching international markets. This tightening has helped diesel prices rise faster than regular gasoline in the United States.
Inventories
US inventories also remain a concern. The US Energy Information Administration expects distillate inventories, which include diesel and heating oil, to fall below 100 million barrels and remain below the recent five-year range for an extended period. EIA said tight global distillate markets and lower refinery production in the Middle East, Russia and China have supported higher prices.
AAA reported the national average for regular gasoline at $4.2770 on September 10, well below the diesel average of $5.9773. The gap matters because diesel powers much of the country’s freight system, including long-haul trucks, farm machinery, construction equipment and parts of the rail and shipping network.
Freight costs
Higher freight costs can spread beyond the fuel market. Trucking companies, farms, contractors and distributors may face larger operating bills, and some of those costs can eventually reach consumers through higher prices for food, building materials and other goods.
The near-term outlook remains uncertain. EIA expects US retail diesel prices to stay elevated through the final months of 2026 as global distillate inventories remain tight. The agency currently forecasts diesel to average about $5.55 a gallon in the fourth quarter of 2026. For consumers and businesses, the key factors to watch are crude oil prices, refinery output, shipping disruptions and diesel inventory levels.
