Diesel prices across the United States fell for the six straight week in the week ending Jan. 2, slipping nearly 0.8 cents to the lowest point since mid-October even as oil prices jumped to a seven-month high on tensions between the United States and Iran.

The average $3.783 price per gallon price left the price up 4.5 cents from the same period a year ago but down 3.8 percent from a month ago, according to the U.S. Energy Information Administration. Diesel prices were the lowest since the week ending Oct. 10, when prices were at $3.749 a gallon.

The decline was the steepest in the Rocky Mountain region, where prices fell 2.5 cents to $3.836 a gallon. The East Coast, Gulf Coast and California saw prices edge up, but the sharpest uptick was no more than a penny.

California was the only region to see gas stay at above the $4 mark, as prices in the Golden State fell less than a penny to $4.046 a gallon.

Prices may reverse their course after crude oil prices rose 4.2 percent on the first day of trading this year, as investor noted manufacturing growth in the U.S. and China. Crude oil for February delivery rose $4.13 to $102.96 a barrel on the New York Mercantile Exchange.