U.S. Diesel Prices Ease as Supply Signals Loosen; Midwest Leads the Pullback
In the week of September 15, 2025, U.S. on-highway diesel prices edged down almost across the board. The national average slipped to $3.739 per gallon, a 2.7-cent decline from the prior week. The move was modest but broad-based, with the Midwest and Rocky Mountains posting the largest week-over-week drops as wholesale markets digested softer crude, signs of ample middle-distillate supply, and the onset of fall refinery maintenance.
Week-over-Week Price Analysis
Nationally, diesel fell by 2.7 cents from $3.766 to $3.739 per gallon, a decline of roughly 0.7% week over week. The Midwest saw the biggest change, down 4.4 cents (−1.2%) to $3.710. The Rocky Mountains slipped 3.2 cents (−0.9%) to $3.722. The East Coast eased 2.4 cents (−0.6%) to $3.748, while the Gulf Coast—still the nation’s cheapest diesel market—dipped 1.5 cents (−0.4%) to $3.389. The West Coast remained the outlier at $4.523, down just 1.0 cent (−0.2%).
Regional Comparison
- National Average: $3.739/gal (−$0.027; −0.7% vs. week of Sept. 8)
- East: $3.748/gal (−$0.024; −0.6%)
- Midwest: $3.710/gal (−$0.044; −1.2%)
- Gulf: $3.389/gal (−$0.015; −0.4%)
- Rocky Mountains: $3.722/gal (−$0.032; −0.9%)
- West: $4.523/gal (−$0.010; −0.2%)
Market Drivers (Sept. 8–15 news and data)
1) Oversupply signals weighed on crude and product prices. Through September 11–12, benchmarks extended losses as markets focused on abundant supply and softening U.S. fuel demand—conditions that typically filter into weaker diesel cracks and pump prices. This followed the IEA’s September Oil Market Report highlighting robust global supply growth, which pressured crude and refined products.
2) Refinery maintenance and changing margins. The IEA’s September report also flagged a 3.5 million b/d drop in global refinery runs from August through October as seasonal maintenance ramps up. While lower runs can tighten product output, the report noted diesel crack weakness, suggesting product markets were already loosening—helping cap retail diesel.
3) U.S. outlook tilted bearish for crude and distillates. The U.S. EIA’s Short-Term Energy Outlook released September 9 projected inventory growth and softer crude prices in the near term—an environment consistent with the modest downtick in retail diesel. In parallel, EIA weekly data for the period ended September 12 (released September 17) showed a sizable 4 million-barrel build in distillate stocks, reinforcing the theme of improved diesel availability.
What It Means for Fleets
For carriers, this is a welcome, if incremental, relief. The sharpest declines in the Midwest likely reflect improving regional supply and softer wholesale pricing, while the Gulf remains the low-cost anchor given proximity to refining centers. The West continues to carry structural premiums tied to regional refining configurations and policy costs, so week-to-week easing there tends to be smaller.
Outlook
Near term, the bias leans slightly lower to sideways for retail diesel if crude remains under pressure from oversupply narratives and if distillate inventories continue to build into fall. Watch two swing factors: 1) refinery maintenance timing—extended outages could tighten regional diesel balances; and 2) seasonal demand—harvest activity in the Midwest and early heating-oil purchases in the Northeast can lift distillate draws, at least locally. Broadly, official outlooks published during the week point to ample supply and softer prices into autumn, but volatility remains a risk if geopolitics or weather disrupts refining or logistics.
Bottom line for truckers: lock in savings where available—particularly in the Gulf and Midwest—monitor regional rack trends, and stay nimble on fuel purchasing strategies as maintenance and seasonal demand can swing differentials quickly.
This article was prepared exclusively for truckstopinsider.com.
This content is the exclusive property of truckstopinsider.com. Reposting is permitted, provided a direct link to the original article is included.
Source of diesel data is the U.S. Energy Information Administration (EIA).
