The national average for diesel fuel climbed to $6.434 per gallon, moving the price within 10 cents of the 2022 inflation adjusted peak of $6.58. National gasoline averages reached $4.47 per gallon, approaching the 2026 high set on May 20. Spot diesel prices in the Great Lakes region topped $240 per barrel, the highest rate in the country, while regional averages in Michigan, Ohio, Illinois, and Indiana trend toward $7 per gallon.

Market indicators suggest national gasoline averages will exceed $4.45 per gallon by Sept 18, with the sharpest increases concentrated in the Great Lakes states. Prompt diesel timespreads remain below record levels established in 2022 and earlier this year despite the current retail surge. These price pressures coincide with retail gasoline costs catching a strong bid in the U.S. interior.