Diesel Prices Drop After Memorial Day, Gas Hits $4.56 National Average

Why did diesel prices drop after Memorial Day?

National diesel and gasoline prices fell in the days following Memorial Day weekend, according to AAA data released May 28. The national gasoline average stands at $4.559 per gallon, down from recent highs but still $1.40 higher than this time last year. The decline follows a volatile two-week stretch in which Brent crude swung from $99.80 to $90.78 on Iran ceasefire speculation, then recovered to the mid-$90s as the Strait of Hormuz remained closed.

AAA's current gasoline figure sits 8 cents above the Energy Information Administration's estimate for the same period, a gap that typically signals regional variation. Diesel prices were not broken out in the AAA release, but the national diesel average has tracked 60 to 80 cents above gasoline throughout May, putting the implied diesel average near $5.15 to $5.35 per gallon depending on region.

How does $4.56 gas compare to prior years?

Current pump prices sit close to Memorial Day 2022 levels, when the national gasoline average hit $4.61. That year marked the post-pandemic demand surge and the start of the Russia-Ukraine war. Four years later, the driver is different but the price is nearly identical. The Strait of Hormuz has been closed since late April following U.S. strikes on Iranian naval assets, cutting roughly 20% of global oil supply and adding a sustained $20 to $25 premium to Brent crude.

For a 10-truck fleet running 100,000 miles per month at 6 mpg, the $1.40 year-over-year increase in diesel costs an extra $23,333 per month compared to May 2025, or $2,333 per truck. That assumes diesel tracks 70 cents above the gasoline figure AAA cited. Fleets that locked fuel surcharges to 2025 baselines are eating that delta.

What keeps fuel prices elevated into summer?

AAA cited two factors: rising gasoline demand as summer travel begins and the prolonged Strait of Hormuz closure. Memorial Day weekend typically marks the start of the 100-day summer driving season, when gasoline demand climbs 5% to 8% and refiners shift to more expensive summer-blend formulations. Diesel demand does not follow the same seasonal curve, but refinery economics mean diesel prices rise when gasoline margins tighten.

The Hormuz closure is the larger variable. As long as the strait remains impassable, Brent crude will carry a war premium. Diesel lags crude price moves by 10 to 14 days, so the recent pullback in oil from $99.80 to the low $90s has not yet shown up at the pump. If crude holds near $93 to $95 through mid-June, diesel could drop 8 to 12 cents by the third week of the month. If tensions escalate or the closure extends into July, the current $5.15 to $5.35 range becomes the floor.

What this means for settlement statements

Fuel surcharges tied to the Department of Energy's weekly diesel index will adjust downward in early June if the post-Memorial Day decline holds. Fleets running on contract lanes with lagging FSC formulas (14-day or 30-day averages) will see relief two to four weeks after pump prices drop. Spot market operators feel the change immediately, but only if brokers pass through the FSC adjustment. In a soft freight market, brokers often pocket fuel savings rather than raising the linehaul rate.

The $1.40 year-over-year gap is the number that matters for annual budgets and driver pay. A solo owner-operator running 10,000 miles per month at 6 mpg burns 1,667 gallons. At $1.40 more per gallon than last May, that is an extra $2,333 per month in fuel cost, or $28,000 annualized. Fuel cards offering 10 to 15 cents per gallon in rebates claw back $1,667 to $2,500 of that, but the gap remains wide enough to erase most of the per-mile rate gains fleets saw in late 2025.

Watch the EIA's weekly diesel report and AAA's daily tracker through mid-June. If diesel drops below $5.00 nationally, the Hormuz premium is unwinding. If it holds above $5.20, the war cost is sticky and fleets should plan for elevated fuel through summer.