Cloud Point is the temperature at which waxy solids first appear during cooling of diesel fuel. Keeping diesel fuel at cloud point over an extended period of time or cooling the fuel further will result in more extensive formation of wax solids.

Since fuel filters are vulnerable to plugging below this critical temperature, cloud point is the "fail-safe" operability standard adopted by the petroleum industry. It is also the primary cold flow property recommended by the Engine Manufacturers Association and the American Trucking Association's Technology Maintenance Council.