SPOKANE — Diesel prices remain near record levels in Washington state despite easing slightly from a historic peak reached earlier this fall, capping a year marked by dramatic price swings that strained farmers, truckers and businesses dependent on fuel. 

In October, diesel averaged $7.30 per gallon in Washington, compared with $6.27 nationally, according to AAA. Among regional markets, Walla Walla posted the highest average at $7.43 per gallon, while Wenatchee averaged $7.32, Spokane $7.22 and Yakima $7.17. 

Those prices are slightly below September levels, when Washington’s statewide average reached $7.32 per gallon and the national average climbed to $6.32. AAA recorded the highest diesel average on record Sept. 23 at $7.47 per gallon. 

The record-setting prices marked the culmination of months of increases that began much earlier in the year. 

In January, diesel averaged $3.51 per gallon nationally and $4.62 in Washington. Regional prices ranged from $4.35 in Spokane to $4.67 in Walla Walla. 

Prices rose steadily through February, when the national average reached $3.66 per gallon and Washington climbed to $4.79. The increases accelerated dramatically in March as global energy markets reacted to supply disruptions and geopolitical uncertainty. 

By March, diesel averaged $4.83 nationally and $5.72 in Washington. Wenatchee recorded an average price of $5.73 per gallon while Spokane reached $5.72. 

The market tightened further in April, producing one of the largest monthly increases of the year. Washington’s average price surged to $6.94 per gallon, while the national average climbed to $5.67. Communities across Central and Eastern Washington saw average prices above $6.60 per gallon. 

Although prices eased somewhat during late spring, fuel remained historically expensive. Washington’s diesel average slipped from $6.77 in May to $6.42 in June. National averages also fell from $5.65 to $5.19 during the same period. 

The downward trend continued into July, when Washington’s average dipped below $6 per gallon for the first time since early spring, reaching $5.96. Spokane reported an average of $5.10 per gallon, the lowest among the cities tracked by AAA. 

The relief proved temporary. 

Diesel prices began climbing again in August, with Washington averaging $6.22 per gallon. Just a month later, prices surged past the $7 mark statewide as diesel supplies tightened and global oil markets faced renewed disruptions. 

According to the U.S. Energy Information Administration, diesel markets have been among the tightest segments of the global energy sector this year. In its latest Short-Term Energy Outlook, the agency said higher crude oil prices and strong demand for distillate fuels helped drive diesel prices sharply higher. 

The agency noted that East Coast distillate inventories fell 32% below their five-year seasonal average in September, reflecting continued supply constraints. At the same time, ongoing disruptions affecting oil exports from the Middle East contributed to higher crude prices worldwide. 

The EIA now expects Brent crude oil to average $105 per barrel during the fourth quarter of 2026, significantly higher than earlier forecasts. The agency cited continued concerns over oil transportation routes and refinery demand for diesel fuel. 

Despite the current market pressures, forecasters expect prices to decline next year. 

The EIA projects retail diesel prices will average about $4.50 per gallon nationwide in 2027 as oil production increases and fuel inventories gradually recover. The agency expects global supply chains to improve as exports from the Middle East stabilize and inventory levels rebuild. 

For now, however, diesel remains significantly more expensive than it was at the start of the year. Washington motorists and businesses have seen average prices rise from $4.62 per gallon in January to more than $7 per gallon this fall, making this year one that brought some of the highest diesel prices ever recorded. 

    Diesel prices in Washington reached an all-time high in September at $7.47. Some relief was found in October with prices going down nearly 17 cents a gallon.
  

    Nance Beston