For previous eight years' information, see:

• Cold Hardiness 2016-2017
• Cold Hardiness 2015-2016
• Cold Hardiness 2014-2015
• Cold Hardiness 2013-2014
• Cold Hardiness 2012-2013
• Cold Hardiness 2011-2012
• Cold Hardiness 2010-2011
• Cold Hardiness 2009-2010