Diesel prices in the U.S. surged to an all-time high on Friday due to the ongoing war in Iran and issues with global refining capabilities, which have tightened fuel supplies significantly.
The average national price for diesel hit $5.85 per gallon, exceeding the previous national record set in 2022 during the energy crisis that followed Russia’s invasion of Ukraine while Joe Biden was president. In February, the average diesel price was $3.72, which was shortly before the conflict in Iran began.
In fact, U.S. diesel prices broke the $5 per gallon barrier in the spring of 2022 amid rising tensions in Ukraine, peaking at about $5.81 during the week of June 20, 2022. However, that was still slightly lower than the peak recorded during the latter part of the Trump administration.
Gasoline prices are also on the rise, with the national average reaching around $4.15 per gallon. This spike in prices seems to align with rising crude oil costs. On Friday, Brent crude, which is the global oil benchmark, was trading at about $96 per barrel as energy supply disruptions persisted, according to the American Automobile Association.
Most goods in the U.S. are moved by trucks and trains that run on diesel, and diesel also fuels much of the farming and construction equipment, so higher diesel prices can lead to increased transportation and operational costs for businesses.
Diesel just hit a four-year high, and it barely made the news.
The national average is back above $5.60 a gallon, up roughly $2 from a year ago, as the Iran war and hits on Russian refineries choke global supply. Gasoline gets the headlines at $4. Diesel runs the economy.
This… pic.twitter.com/dfRjIiakyQ
— Kurt S. Altrichter, CRPS® (@kurtsaltrichter) September 4, 2026
Back in January 2021, when Biden took office, diesel was around $2.70 per gallon and gradually increased throughout that year. Price surges were particularly noticeable in early 2022, with a jump from about $3.61 in January to over $5 by March, where they remained high for quite some time.
In May 2022, prices soared to a then-record $5.56 per gallon, which was challenging for many Americans facing high fuel costs. By June, the national average had increased even more, reaching about $5.78, as reported back then.
Although prices did decrease from those levels eventually, diesel fell to below $4 at certain points in 2023 and averaged around $3.76 in 2024, which was Biden’s final full year in office.
The energy market has experienced considerable disruptions since the U.S. and Israel initiated strikes on Iran on February 28. The Strait of Hormuz is a crucial energy transit route, and about 20% of global petroleum consumption passed through this area in the first half of 2025.
According to estimates, roughly 20.9 million barrels per day traversed the Strait during that period, and alternatives for transporting this volume are limited if the strait were ever closed.
The ongoing conflict has also impacted infrastructure necessary for refining crude oil into usable fuels. Notably, a major Saudi refinery was shut down due to a drone strike early in the conflict, worsening supplies for diesel and other processed petroleum products.
Furthermore, the ongoing war between Russia and Ukraine is also affecting global refined fuel supplies. Ukrainian strikes have disrupted Russian refining capabilities, while Russia has imposed restrictions on refined fuel exports through the end of September.
American refiners are ramping up production in response to constrained supplies from abroad. The gap between crude oil prices and the prices of refined petroleum products, known as the “crack spread,” has increased as the cost of refined fuels has risen.
