US diesel price hits record $6.49: How much prices have surged since Hormuz crisis

US diesel prices have climbed to a record $6.49 a gallon, adding to mounting pressure on American consumers, truckers, farmers and businesses as prolonged disruptions around the Strait of Hormuz squeeze global fuel supplies. 

The national average for diesel reached $6.4866 a gallon on September 19, according to the American Automobile Association (AAA), surpassing its previous record. The price was $6.16 a week earlier, meaning diesel has risen by about 33 cents, or 5.3%, in just one week. AAA's data also show diesel is now nearly 75% more expensive than a year ago, when the national average was $3.71.

The increase comes as the Strait of Hormuz remains severely disrupted following the outbreak of the US-Iran conflict on February 28. Iran's effective closure of the waterway, through which roughly one-fifth of global oil and LNG supplies normally move, has fundamentally altered global energy flows.

How much has diesel risen since the Hormuz crisis? 

For a like-for-like comparison, the latest AAA figure before the February 28 conflict was $3.75 a gallon on February 27. Against the September 19 record of $6.49, the increase is: 

The February 27 baseline is consistent with contemporary AAA-based reporting, while EIA data put the national weekly diesel average at about $3.81 on February 23. 

That means the typical US diesel customer is now paying roughly 73% more per gallon than immediately before the Hormuz crisis. 

The rise has not been linear. EIA data show the national weekly diesel average reached $5.97 by September 7 and $6.29 by September 14, before AAA's daily reading moved to $6.49 on September 19.

Why is diesel rising so sharply? 

The problem is no longer simply the price of crude oil. 

The US Energy Information Administration says diesel prices reflect crude costs, refining margins, distribution expenses, taxes and the diesel "crack spread" — the difference between crude input costs and wholesale diesel prices. Tight global distillate supplies and elevated crude prices have pushed both crude costs and refining margins higher.

The disruption around Hormuz has compounded that pressure. 

The waterway normally handles about 20% of global crude and LNG flows. After the February conflict, shipping through the strait collapsed, forcing producers and traders to rely on alternative routes while reducing or delaying exports. Reuters reported in March that oil exports from eight major Middle Eastern Gulf producers had fallen by at least 60% from February levels. (Reuters) 

The squeeze has also been aggravated by attacks on Russian refineries and disruptions to Middle Eastern refining and export infrastructure. The US has consequently become an important supplier of refined petroleum products to markets facing shortages, putting additional pressure on domestic diesel inventories. (The Wall Street Journal) 

Why diesel matters more than gasoline 

Diesel's importance goes far beyond the fuel tank. It powers a large part of the US freight network, including heavy trucks, trains, farm machinery and fishing vessels. It is also embedded in the production and transportation of food. 

That makes diesel demand less flexible than gasoline demand. A household can potentially reduce discretionary driving, combine trips or switch to public transport. A trucking company moving food or industrial goods has far fewer immediate alternatives. 

This is why a diesel shock can spread through the economy even when consumers are not directly buying diesel themselves: higher fuel costs can raise freight rates, farm costs, food prices, industrial costs and ultimately consumer prices. 

California is facing an even bigger fuel shock 

California is the most expensive major US fuel market. AAA puts the state's average diesel price at $8.4161 a gallon, while regular gasoline has reached $6.1372 a gallon. 

That means California diesel is almost $2 a gallon above the national average, highlighting how regional taxes, supply constraints, refinery conditions and fuel specifications can amplify the impact of a global oil shock. 

Gasoline is rising too — but diesel is under greater pressure 

Gasoline has also moved sharply higher. AAA's national average for regular gasoline stood at $4.4759 a gallon on September 19, up from $2.98 around February 27. That represents an increase of roughly 50% since the immediate pre-Hormuz-crisis level.

But diesel's roughly 73% increase over the same period shows where the current supply stress is most acute. 

The reason is increasingly a shortage of refined fuels rather than simply a shortage of crude oil. Refinery disruptions in Russia and the Gulf, constrained shipping routes and strong demand for US exports have tightened the international diesel market. 

What happens next? 

The outlook depends heavily on whether oil and refined-fuel flows through the Gulf normalise. 

The Strait of Hormuz remains severely restricted, with Reuters reporting only a handful of commodity vessels passing through the waterway on some recent days compared with roughly 125 daily transits before the war.

At the same time, attacks on Saudi Arabia's East-West pipeline have removed another important alternative route for moving crude to export terminals outside the Gulf.

Chevron CEO Mike Wirth has warned that the global oil market has been losing the commercial and strategic buffers that previously helped contain prices, including inventories and spare capacity.