The national average price of gas increased 6.1 cents to $3.143. The national average is down -8.6 cents from a month ago and down -50.6 cents from a year ago. The national average price of diesel has decreased -2.7 cents in the last week and stands at $3.473 per gallon. The median US gas price is $2.91 per gallon, down -8 cents from last week and about -17 cents lower than the national average.