The national average price of gas increased 2.0 cents to $3.12 last week. The national average is down -12.0 cents from a month ago and down -49.6 cents from a year ago. The national average price of diesel has increased 0.2 cents in the last week and stands at $3.501 per gallon. The median US gas price is $2.99 per gallon, up 3 cents from last week and about -13 cents lower than the national average.