In most cases, this parameter is not necessary. Some regions of the world do not recognize the ending of daylight savings time as the last Sunday in October. If your server is in a region where this is true, use this parameter to specify the exact date when DST will end. Use this setting along with DST_Begin_Date, which specifies when daylight savings time begins.
See the settings DST_Begin_Date and DSTlaw for additional ways to adjust the time stamp for daylight savings.