US retail diesel prices have surged to a record high of $5.85 per gallon as of September 4, 2026. This increase is primarily attributed to the ongoing war with Iran, which has been disrupting the global flow of fuel for the past six months. This record price significantly surpasses the average of $3.71 per gallon recorded a year ago, as well as previous highs seen after Russia's invasion of Ukraine.
The conflict in Iran, particularly the effective closure of the Strait of Hormuz – a critical waterway through which one-fifth of the world's oil is transported – has led to a substantial increase in wholesale oil prices, directly impacting diesel costs. Diesel is a crucial fuel for commercial vehicles, including trucks, trains, buses, and farming and construction equipment. Consequently, higher diesel prices translate to increased transportation costs across various freight and delivery networks.
Businesses are already facing higher bills due to these fuel costs, with some passing these expenses to consumers through added fees on online orders and packages. Shoppers are expected to see more sticker shock on store shelves as these costs trickle down. The soaring fuel prices have also become a significant political issue ahead of the crucial midterm elections in November, with President Donald Trump's approval rating falling to 33% amid public discontent over the conflict and its economic repercussions.
While the national average is $5.85, prices vary significantly across the US, with Western states experiencing higher costs due to factors like tax differences and distance from oil producers. For instance, Washington state's average diesel price is $6.81 per gallon, up from $5.03 a year ago. In addition to diesel, gasoline prices are also historically high, averaging $4.15 per gallon compared to $3.20 a year ago.
Despite the rising costs, US President Trump recently pledged to lower gas prices through an oil deal with Venezuela. This agreement, announced on Saturday, involves the development of 17 strategic oil fields with a proven potential of 65 billion barrels, anticipating over $100 billion in investment and more than $209 billion in taxes for Venezuela. The US government will retain 55% control of a joint venture with an "experienced private operator in Venezuela," though some analysts remain skeptical about the deal's potential to overcome long-standing obstacles in Venezuela's oil industry.
