That's according to a survey released Sunday.
Industry analyst Trilby Lundberg says the increase stems from a jump in the price of ethanol used to make gasoline.
She says another reason for the rise is that U.S. refiners are starting to switch over to more expensive summer-blend gasoline.
The average prices of a gallon of midgrade and premium gas were $3.74 and $3.89, respectively. Diesel averaged $4.02 per gallon.
Of the cities surveyed in the Lower 48 states, Billings, Mont., has the lowest average price at $3.18 a gallon and Los Angeles has the highest average price at $4.
