Diesel prices hit record $5.85 per gallon, complicating US inflation fight

Diesel fuel just became the most expensive it has ever been in the United States. The national average retail price hit $5.85 per gallon as of September 4, 2026, eclipsing the previous record of $5.82 per gallon set during the energy shock of June 2022. A year ago, that same gallon cost $3.71. That’s a 58% increase in twelve months, and it’s landing squarely on the sectors that move, build, and feed the country. Why diesel, why now Two overlapping conflicts are squeezing global diesel supply from both ends. The US-Iran conflict, which began on February 28, 2026, has created persistent disruptions in the Strait of Hormuz. Before the conflict, roughly 10% of the world’s seaborne diesel supply transited through that narrow waterway between Iran and the Arabian Peninsula. Meanwhile, ongoing strikes on Russian refineries tied to the Russia-Ukraine war have further constrained supply. The combined effect has pushed diesel crack spreads, the difference between the price of crude oil and refined diesel, to nearly $108 per barrel in early September 2026. Prices had actually dipped below $5 per gallon in late June 2026, reaching $4.98. By early September, the upward march resumed with force....