Diesel prices in the U.S. have hit an unprecedented average of $5.85 a gallon, driven by the persistent six-month conflict with Iran which has significantly disrupted global fuel supplies. This new record surpasses the previous high seen after Russia's full-scale invasion of Ukraine. The war has constrained the flow of oil, particularly due to Iran effectively closing the Strait of Hormuz, a crucial waterway for about a fifth of the world's oil.

The surge in diesel prices is having a substantial impact on the economy, especially on transportation costs for a wide array of goods. Diesel is vital for commercial vehicles like trucks, trains, buses, and farming equipment. Higher fuel costs translate to increased expenses for businesses across sectors, which are often passed on to consumers. For instance, Amazon implemented a 3.5% fuel and logistics surcharge, and major carriers like UPS, FedEx, and the USPS have also added fees, contributing to higher prices for groceries, clothing, and other consumer goods.

The economic pain is considerable, with Americans paying an estimated $97 billion more due to higher gas and diesel prices since the Iran war began, averaging over $740 per U.S. household. President Donald Trump has responded by meeting with refining executives and announcing an oil deal with Venezuela in an effort to stabilize prices. Despite these efforts, the situation has led to a decline in Trump's approval rating to 33%, with only 31% approving of the conflict, posing challenges for Republicans ahead of the November midterm elections.

While the national average is $5.85 a gallon, there's significant regional variation, with Western states experiencing higher prices due to factors like tax differences and distance from oil producers. For example, Washington state sees average diesel prices at $6.81 a gallon. The current prices, while historically high, are still below inflation-adjusted peaks from 2008 and 2022. However, analysts warn that the situation could worsen, especially for African and Asian countries heavily reliant on Middle Eastern imports, as global refined oil product stocks dwindle.