The average cost of a gallon of gasoline in South Dakota has topped four dollars.

Wednesday marks the first time the state has passed that threshold.

Mark Medieja with AAA of South Dakota says he isn't surprised that South Dakota hit the mark.

Medieja says drivers in the state have actually been fortunate because the national average has been above four dollars for at least a week.

He expects gas prices to remain somewhat stable until the Fourth of July weekend. But he says anything could happen to make the market volatile once again.