U.S. Diesel Prices Hit Record Highs Amid Iran War

U.S. diesel fuel prices reached a record national average of $6.28 per gallon on September 14, 2026, marking a more than 78% increase since the start of the war against Iran in February. The price surge follows a steady climb from $5.85 per gallon on September 4 to $6.05 per gallon by September 11, with some regions like Montana seeing prices hit $6.29 per gallon by late September.

John Thune, the U.S. Senate Majority Leader, proposed a ban on diesel exports to increase domestic availability as the country faces its lowest distillate inventories since 1951. The crisis is driven by the closure of the Strait of Hormuz, a July 2026 ban on diesel exports by Russia to support its military, and a long-term decline in U.S. refining capacity caused by environmental regulations. U.S. refineries are currently operating at nearly 98% capacity.

The price spikes have created severe financial strain for the agricultural sector during the harvest season for corn, soybeans, and potatoes. The United States Congressional Joint Economic Committee reported that crop planting costs increased by $1.4 billion. Additionally, the fuel shortage is expected to raise heating oil prices in the northeastern U.S. by 30% or more for the upcoming winter.