Diesel fuel

[rynosback]

Does anyone know when and how far the winter blend goes?

[RustyJC]

Not an easy question to answer, insofar as the United States is concerned. From Wikipedia:

United States

In the United States there is no legislation on a fixed time frame when winter diesel must meet a specific temperature characteristic. The ASTM D 975 standard does not specify the cold flow requirements of diesel fuel. Instead, it suggests that the cloud point be no more than 6°C higher than the 10th percentile minimum ambient temperature for the month the fuel will be used. The 10th percentile temperature corresponds to the minimum temperature that would be reached no more than 3 days out of 30 for the month (decile). The ASTM D 975 contains overview maps that show the expected tenth percentile temperature for every month for each state.[34]

Using these guidelines gas stations offer "winter ready diesel" for sale to the Motorist - there are two ways to achieve this:

winter blend - the gas station has blended the No.2 diesel with No.1(kerosene) by some percentage.
winterized diesel - the No.2 diesel has been treated with additives by the diesel supplier.
As the treatment with additives (1:40000[35]) is a cheaper way to enhance No.2 fuel in winter, most stations offer winterized diesel in cold weather conditions. In regions with colder weather, most gas stations offer No.1 fuel at the same pump allowing drivers to decide for themselves on a winter blend.