The U.S. Energy Information Administration projected in its May Short-Term Energy Outlook that the national on-highway diesel fuel price will average $4.76 per gallon in 2026, a slight decrease from the $4.80 forecast issued the previous month.
The agency's quarterly breakdown showed diesel averaging $5.36 per gallon in the second quarter of 2026, easing to $4.94 in the third quarter and $4.73 in the fourth quarter. Both the April and May outlooks agreed that first quarter 2026 diesel averaged $4.06 per gallon, following a full-year 2025 average of $3.66. As of May 21, AAA data put the national average diesel price at $5.656 per gallon, down slightly from the prior week's $5.667 but still well above the year-ago average of $3.554.
Regional differences remain wide. Of the five Petroleum Administration for Defense Districts the EIA tracks, the Gulf Coast posted the lowest on-highway diesel price in mid-May at $5.122 per gallon, while the West Coast carried the highest at $6.524. State-level data from GasBuddy showed the lowest average diesel prices concentrated in the South, with Texas at $4.96 per gallon, Louisiana at $5.02, and Mississippi at $5.04, compared with California's $7.40 and Hawaii's $7.21.
GasBuddy's head of petroleum analysis noted that tight global oil inventories continue to leave gasoline and diesel prices sensitive to geopolitical developments, meaning near-term volatility could persist even as the annual forecast points modestly lower.
Source: Rigzone - https://www.rigzone.com/news/usa_eia_reveals_latest_usa_diesel_price_forecast_for_2026-21-may-2026-183750-article/