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US Diesel Hits $6.529 Per Gallon on September 21, Up From $6.285 Week Prior as Hormuz Disruption and Refinery Constraints Tighten Distillate Supply Despite Crude Price Retreat
Sources: Energy Information Administration weekly Gasoline and Diesel Fuel Update released September 22, 2026; IndexBox (diesel $6.529, September 21; $6.285, September 14; $2.780 above year-ago); USDA AgTransport dataset (California $8.246, Lower Atlantic $6.139, week ended September 21); OilPrice.com (year-to-date average $4.895 through September 7; 2022 record $4.989; inventories 107.9 million barrels September 11, lowest since 1982); EIA Short-Term Energy Outlook September 2026 (forecast inventories below 100 million barrels, below five-year low through 2027); Chase analysis via IndexBox (refinery capacity constraints, distillate competition); Trading Economics (Brent $98.47, September 22; WTI around $95.59).
United States on-highway diesel prices reached $6.529 per gallon nationally on September 21, 2026, up $0.244 from $6.285 the prior week and $2.780 above the year-ago level, according to the Energy Information Administration's weekly retail fuel price update released September 22. California posted the highest regional price at $8.246 per gallon, while the Lower Atlantic recorded the lowest at $6.139, according to USDA AgTransport data for the week ended September 21. The continued diesel price escalation occurred even as crude oil prices fell for a fifth consecutive session, with Brent settling at $98.47 on September 22 and WTI at around $95.59, reflecting the structural tightness in the refined products market that has persisted despite improving crude supply. Diesel inventories remain at historically low levels, with 107.9 million barrels as of September 11 marking the lowest for this time of year since 1982, while refinery constraints and the ongoing Strait of Hormuz disruption continue to limit distillate availability. The Energy Information Administration forecasts US distillate inventories will drop below 100 million barrels in September and remain below the five-year low through much of 2027. Diesel's persistent strength relative to crude reflects the fact that refiners cannot instantly increase diesel production without trade-offs, and that diesel competes for the same refinery capacity as jet fuel and heating oil. Higher diesel prices are embedding cost pressure throughout the economy in trucking, agriculture, construction, and rail, with businesses already passing steeper costs to consumers through added fees on deliveries and shipments. The year-to-date diesel average through September 7 stood at approximately $4.895 per gallon, positioning 2026 to surpass the 2022 annual record of $4.989 if prices remain near current levels through year-end.