SPOKANE, Wash --- Gas prices in Washington state are almost 50 cents higher than the national average.

The average cost for a gallon of gas in Washington state is $2.83 and the national average is $2.35, according to the American Automobile Association. Idaho’s average gas prices are between the two at $2.63 a gallon.

Some things that can contribute to higher gas prices are the price of crude oil, low gasoline inventory, price of gasoline additives and zone pricing, according to the Washington state attorney general’s office. Most of those are self-explanatory but what is zone pricing? It is a practice where refiners sell gasoline to retailers at wholesale prices that differ across geographic areas. Refiners charge more in areas where demand is high and/or competition is low, which means zone pricing is set by the refiners based on supply and demand.

When you look at the gas price heat map on GasBuddy’s website, you can see the fluctuations in prices within the Spokane area. Prices range from around $2.40 a gallon in Fairfield to about $2.80 a gallon in Cheney.

Washington, California, Alaska and Hawai’i have the highest average gas prices in the nation at around $2.80 a gallon. Alabama, South Carolina, Arkansas and Mississippi have some of the lowest average gas prices in the nation at around $2.10 a gallon.

For specific gas prices of businesses go here, the website has information about where to go and exactly how much the gas costs there.

For gas mileage tips from the U.S. Department of Energy go here.