The national average price for a gallon of diesel fell 1.6 cents to $2.58 for the week ending December 31, according to the Energy Information Administration.

Although prices fell in all regions, the biggest decline was in the Central Atlantic, falling 2.9 cents to $2.681. The cheapest region to fill up was the Gulf Coast, at $2.50 after a 1.4-cent drop. California once again was the most expensive region to buy diesel, as prices were the most stable there, falling only 0.2 cents to $2.883.

For more information, go to http://tonto.eia.doe.gov/oog/info/wohdp/diesel.asp