U.S. Diesel Prices Nudge Higher Week-Over-Week; Regional Moves Remain Mixed
For the week of September 22, 2025, the national average on-highway diesel price ticked up a penny to $3.749 per gallon from $3.739 the prior week. Gains were concentrated in the Midwest and Rocky Mountain regions, while the East Coast was essentially flat and the West Coast held steady at the nation’s highest levels. Overall, the market reflected modest week-over-week movement amid easing crude prices and shifting refinery dynamics.
Price Analysis: Week of 2025-09-22 vs. 2025-09-15
Nationally, diesel rose by 1.0 cent (+0.27%) to $3.749/gal. Regionally, the Midwest posted the largest increase, up 2.1 cents (+0.57%) to $3.731/gal, followed by the Rocky Mountains, up 2.5 cents (+0.67%) to $3.747/gal. The Gulf Coast, still the nation’s lowest-priced market, edged up 1.1 cents (+0.32%) to $3.400/gal. The East Coast slipped by 0.3 cents (-0.08%) to $3.745/gal, and the West Coast was effectively unchanged, up 0.1 cent (+0.02%) to $4.524/gal. These muted changes align with broader petroleum signals: a mid-September build in distillate stocks and a late-week fade in crude prices both tended to cap diesel’s upside.
Regional Comparison
- National Average: $3.749/gal (+$0.010 w/w)
- East Coast: $3.745/gal (-$0.003 w/w)
- Midwest: $3.731/gal (+$0.021 w/w)
- Gulf Coast: $3.400/gal (+$0.011 w/w)
- Rocky Mountain: $3.747/gal (+$0.025 w/w)
- West Coast: $4.524/gal (+$0.001 w/w)
The West Coast remains the premium market, while the Gulf Coast continues to anchor the national average with the lowest regional price. The Midwest’s uptick, paired with a similar move in the Rockies, suggests localized firmness even as national indicators leaned neutral.
Market Drivers (news from Sept. 15–22)
- Distillate inventories increased sharply. The EIA’s weekly data for the period ending September 12 showed U.S. distillate stocks (which include diesel) rising by 4.0 million barrels, while refinery utilization slipped to 93.3%. A larger distillate build tends to temper diesel price gains by signaling improved supply.
- Crude prices softened on oversupply and demand worries. Into September 19, oil retreated despite the Fed’s rate cut, with analysts pointing to robust global supply and refinery maintenance season as drags—factors that often ease diesel’s feedstock costs with a lag.
- Gulf Coast diesel production constraints lingered. On September 22, industry reporting indicated Marathon’s 631,000 bpd Galveston Bay refinery would complete repairs to a key hydrotreater by mid-October, implying near-term diesel output there remains limited—one reason Gulf prices didn’t fall further.
What It Means for Fleets
With crude drifting lower and distillate stocks improving, national retail diesel is likely to remain rangebound near-term. However, localized refinery issues and ongoing maintenance can still create pockets of tightness—particularly along the Gulf Coast and in adjacent supply lanes—while the West Coast premium should persist given structural constraints. Keep an eye on mid-week EIA inventory updates and refinery run rates; if distillate builds continue and crude stays subdued, price pressure may ease modestly. Conversely, any unplanned outages or storm-related disruptions could quickly tighten regional supply and lift rack prices.
Looking slightly ahead, OPEC+ has signaled a smaller production increase starting in October, part of its broader shift toward regaining market share. The slower pace suggests limited immediate impact, but the overall supply posture remains a headwind for crude—and by extension a stabilizing force for diesel—unless demand surprises to the upside.
This article was prepared exclusively for truckstopinsider.com.
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Source of diesel data is the U.S. Energy Information Administration (EIA).
