Back in the early 20th century, US regulators decreed that the official definition of a gallon of gasoline was 231 cubic inches at 60 degrees Fahrenheit. All well and good, but the problem is that gasoline expands somewhat as temperature increases, meaning that you're actually getting less energy per dollar when you buy gas warmer than 60º F. According to consumer-watchdog types, this translates to something like 3 to 9 cents extra per gallon at the pump this summer. The House Subcommittee on Domestic Policy, chaired by presidential hopeful Dennis Kucinich, says retailers should adjust prices based on fuel temperature; retailers say such a move would cause the destruction of the American Way Of Life.
As fuel expands, so does cost [Houston Chronicle]
Guess What Yesterday Was? Record High Gas Prices Day! [internal]