The Department of Energy's weekly price survey released on Monday posted the national average price for diesel at $3.801 a gallon -- the highest price recorded in the previous month, and nearly 73 cents a gallon higher that it was a year ago.
Benchmark crude finished down 42 cents at $86.38 per barrel in New York on Monday, while Brent crude, used to price international varieties of oil, fell $2.07 to end at $110.16 a barrel in London, the Associated Press reports.
Oil has lost 24 percent since May. Investors are concerned about weak demand for gasoline here in the U.S., and budget problems in Greece.
Prices had begun to rise last week, but on Monday, German finance chief Wolfgang Schaeuble dampened expectations that European finance ministers would be able hammer out a solution at an upcoming summit.
Gasoline pump prices rose a half penny to a national average of $3.462 per gallon, according to the Oil Price Information Service. A gallon of regular has fallen about 52 cents from its peak near $4 per gallon on May 5, but it's still nearly 63 cents higher than the same time last year.