Diesel set a record $6.29 a gallon, and its premium over gasoline is a record $1.97

The national average retail price of diesel was $6.285 a gallon on September 14, 2026, in the Energy Information Administration’s weekly survey. That is the highest reading in a series that begins in March 1994 and the first above $6. The old record, $5.81 on June 20, 2022, stood until the week before, when diesel reached $5.967; the new figure is 8.2% above it. Diesel has risen $0.686 in two weeks, is up 79.6% from $3.50 at the end of 2025 and up 68.1% from $3.739 a year earlier. The largest weekly increase in the record also belongs to this year: $0.962 in the week of March 9.

Gasoline has not followed. Regular averaged $4.319 on the same day, 13.7% below its record of $5.006 from June 13, 2022. The gap between the two fuels, $1.966 a gallon, is the widest in the record, past the previous high of $1.607 on November 28, 2022. Upstream, West Texas Intermediate crude was $107.02 on September 15, up from $87.28 on August 19, and New York Harbor wholesale diesel was $5.338, a tenth of a cent below its record of $5.339 from May 11, 2022. Diesel is the fuel of trucking, rail, farming and construction, so this is a freight and input cost before it is a consumer one. These are nominal prices with no inflation adjustment, and the chart makes no forecast and asserts no cause.