Gas Prices Increase By 9.1 Cents, Diesel Down .5 Cents During Week
Average gasoline prices in Montana have risen 9.1 cents per gallon in the last week, averaging $4.55/g on Monday, May 18, according to GasBuddy’s survey of 615 stations in Montana. Prices in Montana are 70.2 cents per gallon higher than a month ago and stand $1.38/g higher than a year ago. The national average price of diesel has decreased 0.5 cents compared to a week ago and stands at $5.618 per gallon.
According to GasBuddy price reports, the cheapest station in Montana was priced at $4.19/g on Sunday, May 17, while the most expensive was $4.99/g, a difference of 80.0 cents per gallon.
The national average price of gasoline has fallen 1 cent per gallon in the last week, averaging $4.47/g on Monday. The national average is up 45.2 cents per gallon from a month ago and stands $1.33/g higher than a year ago, according to GasBuddy data compiled from more than 11 million weekly price reports covering over 150,000 gas stations across the country.
Historical gasoline prices in Montana and the national average going back five years are: May 18, 2025: $3.17/g (U.S. Average: $3.14/g) May 18, 2024: $3.45/g (U.S. Average: $3.58/g) May 18, 2023: $3.51/g (U.S. Average: $3.52/g) May 18, 2022: $4.33/g (U.S. Average: $4.58/g) May 18, 2021: $2.90/g (U.S. Average: $3.04/g) Neighboring areas and their current gas prices: Idaho- $4.61/g, up 8.8 cents per gallon from last week’s $4.52/g.
Billings- $4.54/g, up 8.0 cents per gallon from last week’s $4.46/g.
Wyoming- $4.49/g, up 11.8 cents per gallon from last week’s $4.37/g.
“The national average price of gasoline spent much of last week drifting lower after jumping early in the week as oil prices softened on hopes that diplomatic progress between the U.S. and Iran could help ease supply concerns,” said Patrick De Haan, head of petroleum analysis at GasBuddy. “However, that optimism faded after President Trump’s meeting with China’s Xi Jinping failed to produce a breakthrough on Iran, while renewed warnings toward Tehran have helped push oil prices higher again. With global oil inventories continuing to trend toward historically tight levels, markets remain extremely sensitive to geopolitical developments and potential supply disruptions. As a result, gasoline and diesel prices are likely to remain volatile, and with Memorial Day approaching, any sustained increase in oil prices could begin pushing retail fuel prices higher again in the weeks ahead.”
