US ULSD diesel crisis pushes national average to $5.55 as Iran war enters fourth month

ULSD diesel prices at the pump have become the most painful energy cost for American consumers and businesses since the Iran war shut the Strait of Hormuz on February 28. The US national average for diesel hit $5.55/gal as of May 22, according to EIA data — up 85% from approximately $3.00/gal at the start of 2026 and $1.45 more per gallon than regular gasoline, which stands at $4.55/gal. (FACT: EIA Weekly Petroleum Status Report via Jalopnik, May 2026) GasBuddy reported that Michigan, Illinois, Ohio, Indiana, Wisconsin, and Minnesota have all breached or are within cents of $6.00/gal diesel. (FACT: AgWeb/GasBuddy, May 5, 2026)

The divergence between diesel and gasoline tells the real story of this crisis. Diesel is the fuel that powers the economy — trucking, agriculture, construction, manufacturing, and school buses all run on it. Gasoline's spread to diesel has widened by roughly $0.50/gal since the war began. At the start of 2026, regular gasoline was below $3.00/gal and diesel was roughly $3.00/gal — nearly equal. (FACT: Jalopnik, May 2026) The $1.00-plus spread now reflects the compounding effect of Middle East distillate supply losses on top of crude price increases, since the Gulf region is a dominant supplier of both the crude grades and the finished middle distillates that yield diesel and jet fuel. (FACT: The Crude Life, April 22, 2026)

US Gulf Coast ULSD spot prices have climbed to multiyear highs. FRED/EIA data shows the Gulf Coast No. 2 ULSD spot price at elevated levels through early May 2026, with volatility tied directly to ceasefire headlines and Hormuz reopening signals. (FACT: FRED — DDFUELUSGULF, May 4, 2026) NYMEX ULSD front-month futures spiked as high as $3.5755/gal on March 5 — the highest since January 2023 — on news of Iranian attacks in the Persian Gulf. (FACT: DTN, March 5, 2026) While futures have moderated from that spike, physical diesel prices remain elevated because of actual supply tightness rather than speculative positioning.

The impact on end-users is severe and mounting. Industry analysts warn that sustained diesel prices above $6/gal could drive 6,000 to 10,000 carriers out of the market in 2026 — primarily small, independent owner-operators with thin margins who cannot pass fuel costs through to shippers fast enough. (FACT: The Crude Life, April 22, 2026) School districts from Yakima, Washington to Waco, Texas are tapping emergency funding reserves to keep buses running. (FACT: Associated Press via Madison.com, May 18, 2026) A logistics company consuming 50,000 gallons of diesel per month at current prices faces an additional $60,000 per month in fuel costs compared to pre-war levels.

The IEA describes the Strait of Hormuz closure as "the largest supply disruption in the history of the global oil market." (FACT: IEA Oil Market Report, May 13, 2026) Global observed oil inventories drew by 129 million barrels in March and a further 117 million in April, with on-land stocks dropping 170 million barrels in April alone. (FACT: IEA, May 2026) The EIA's Short-Term Energy Outlook acknowledges that while the US is comparatively insulated from outright shortages due to domestic refining capacity, price relief will not be immediate even if the Strait reopens — the supply chain takes weeks to recalibrate. (FACT: EIA STEO, May 12, 2026) The Guardian reported on May 23 that analysts do not expect fuel prices to normalize until 2027. (FACT: The Guardian, May 23, 2026)