(The Center Square) – After five straight weeks of price increases, and last week remaining stagnant, average fuel prices in Washington are again on the rise week over week.

The average price of a gallon of regular unleaded was sitting at $4.18 statewide on Monday, up from $4.13 a week prior according to AAA data.

While fuel prices have been rising slightly for the last few weeks when looking at the national average, this week the price remains flat from the week prior.

“The national average for pump prices dipped to $3.41 before creeping a bit higher over the past two days, and this trend of small increases could persist into next week,” said AAA spokesperson Andrew Gross in a statement.

Citizens of the Evergreen State have to dig deeper into their wallets than most. Washington’s pump prices came in at fourth most expensive nationally being beat out only by Nevada, California, and Hawaii, who filled out third to first on the list. 

Washington’s $4.18 per gallon places it 77 cents per gallon higher than the national average of $3.41 per gallon. That is $1.18 per gallon above the nation’s least expensive fuel costs of $3.00 per gallon, currently paid by Texans.

In Washington, intra-state variance remains high at $1.33 per gallon, up from last week’s $1.24 per gallon. The outliers this week, San Juan and Asotin counties, represent the most and least expensive gas prices statewide at $4.94 and $3.61 per gallon, respectively.

This price variance still largely follows the Cascade Range, with residents to the west paying a higher premium at the pump than residents to the east.

On top of these higher prices, as of Jan. 1 of this year, Washingtonians also have a new cap-and-trade system to pay for at the pump.

According to a recent report by the Washington Policy Center’s Environmental Director Todd Meyers, gas prices in Washington have already spiked 10 cents per gallon relative to California and Oregon.

“What the data show is that prices in Washington state jumped suddenly over the last two weeks much more than the other states on the West Coast,” the report stated.

Ultimately, the full impact of the new carbon tax won’t be known until regular auctions occur. The report notes that the new law “sets a minimum price of $22/metric ton of CO2, which translates to 17 cents per gallon. The price could go as high as $81/MT which would be 65 cents per gallon.”