You really don't need to worry about it unless you fill up in a warm region and drive to a much colder one without using up most of your fuel. The major fuel companies blend the fuel to meet the seasonal temperatures and the ASTM has standardized diesel "pour points" for wintertime diesel fuels.
See the ASTM winter fuel table here:
ASTM pour point temperatures
There are a variety of anti-gel additives available for fuel that will be stored at very cold temps, around zero or less.