MOSES LAKE — Gasoline prices across Washington state, the nation, Grant County, and Adams County have followed a similar trajectory in the first five months of 2026: a steady climb through late winter and early spring, a peak in mid-May, and a modest decline heading into June, according to data from AAA. 

According to data compiled weekly since early January, prices began the year at relatively moderate levels before rising sharply through March and April. In Washington, the statewide average climbed from $3.84 per gallon on January 5 to a peak of $5.78 by May 18, marking an increase of nearly $2 per gallon in just over four months. 

Nationally, prices rose from $2.81 to $4.52 over the same period.

Local trends mirrored the broader pattern. In Grant County, gasoline prices rose from $3.79 in early January to $5.60 in mid-May, while Adams County increased from $3.85 to $5.51, both reflecting significant upward pressure across the region.

Spring surge

The most aggressive price acceleration occurred between early March and mid-May. Washington jumped from $4.37 on March 2 to nearly $5.80 by mid-May, while the national average surged from $3.00 to $4.52. 

Local counties experienced similar increases, with Grant County rising by nearly $1.50 per gallon during that stretch.

This seasonal surge is consistent with typical springtime demand increases, refinery maintenance schedules, and the transition to summer fuel blends. However, additional global factors also played a role in pushing prices higher earlier in the year.

Late-May decline

After peaking in mid-May, prices began to ease slightly. By June 1, the statewide average in Washington had dipped to $5.71, while the national average fell to $4.32. Grant County decreased to $5.50, and Adams County to $5.43.

The recent decline reflects broader trends seen across the country.

“Average gasoline prices declined in all 50 states over the last week, with GasBuddy now tracking 15 states where the average price of gasoline has fallen below $4 per gallon, offering motorists some of the most widespread relief seen in weeks,” Patrick De Haan, head of petroleum analysis at GasBuddy stated. 

De Haan attributed the drop largely to changes in global oil markets and easing supply concerns.

“Much of the decline was driven by falling oil prices and the unwinding of recent price cycles, as growing optimism surrounding a potential U.S.-Iran agreement helped ease concerns over global oil supplies,” he said. 

In addition to gasoline, diesel prices also declined significantly, dropping more than 15 cents per gallon nationwide, which may help reduce transportation and goods costs in the coming weeks.

WA remains well above national average

Despite the recent decline, Washington continues to maintain some of the highest fuel prices in the country. As of June 1, the state average of $5.71 per gallon remains nearly $1.40 higher than the national average of $4.32.

Grant and Adams counties follow a similar pattern, both consistently tracking slightly below the Washington state average but still well above national levels. This gap reflects factors unique to the region, including state fuel taxes, environmental regulations, and supply logistics.

Uncertainty ahead

While drivers are seeing some short-term relief, experts caution that volatility remains a key factor in fuel markets.

De Haan emphasized that the situation is far from stable. 

“However, the coast is anything but clear,” De Haan said. “Oil prices edged higher Sunday evening as uncertainty surrounding a potential deal persisted and renewed Israeli attacks added another layer of geopolitical risk.”

He also noted that retail price cycles could soon push prices back upward:

“While motorists may continue to see some short-term relief, some price-cycling states could soon experience another upward swing as retailers run out of room to lower prices further,” De Haan said. 

Overall trend

Looking at the broader trend since January, prices across all areas remain significantly elevated despite the recent dip. Washington is up nearly $1.87 from January 5 to June 1. The national average is up about $1.51 during the same period. Grant County is up roughly $1.71. Adams County is up about $1.58. 

However, compared to mid-May peaks, prices have declined modestly – off by roughly 7 to 20 cents per gallon depending on location.