Mammoth Mountain, California has one of the longest ski seasons in North America, which averages from November to June. The resort occasionally enjoys a longer season, as in 2005, when it opened in October and did not close until the 4th of July. The 1994–95 season was Mammoth Mountain's longest, over ten months, with the resort operating from October 8 until August 13. The 2016-2017 season was the second snowiest on record, with 618 inches (2010-2011 with 668.5 inches is the resort record), and stayed open until August 6, 2017. January 2017 was the snowiest month in Mammoth history, with 246 inches.
Pictures from my trip in January, 2013.