Schwerdtfeger 00Z temperature 1985 - -16.7 -24.1 -35.6 - -35.1 -46.9 -39.2 -35.5 -26.0 -15.4 -6.7 1986 -6.9 -13.8 -24.7 -30.1 -27.1 -35.6 -37.9 -41.2 -43.5 -26.6 -14.9 -6.7 1987 -4.1 -16.5 -31.1 -34.0 -33.5 -28.2 -34.0 -40.0 -35.6 -26.5 -17.0 -5.2 1988 -5.9 -15.6 -29.9 -30.6 -31.6 -34.2 -34.9 -28.0 -30.9 -21.4 -15.0 -5.4 1989 -5.5 -15.3 -25.0 -28.4 -35.2 -41.2 -37.3 -38.1 -33.9 -25.5 -12.6 -5.1 1990 -5.6 -17.1 -27.0 -30.3 -33.7 -37.7 -38.3 - -39.3 -27.9 -14.2 -4.8 1991 -6.2 -11.7 -27.9 -30.6 -33.9 -29.3 - -38.2 -30.9 -25.4 -14.1 -4.7 1992 -4.4 -16.4 -22.8 -36.9 -32.6 -35.5 -31.2 - - - - - 1993 - -16.1 -28.5 -30.8 -38.2 -32.9 -32.5 - - -29.8 -12.3 -5.8 1994 -4.2 -14.3 -27.8 -25.4 -40.1 -33.0 -32.3 - - - - - 1995 - - - - - - - - - - - - 1996 - -15.9 -28.8 -28.8 -35.8 -35.8 -38.4 -34.0 -31.9 -29.2 -15.0 -6.5 1997 -7.9 -18.9 -31.3 -36.3 -33.2 -33.2 -38.3 -42.4 -35.5 -21.4 -11.4 -7.6 1998 -8.2 -13.4 -27.1 -38.9 -34.9 -27.9 -38.9 -38.0 -40.2 -25.7 -16.6 -7.3 1999 -7.6 -17.1 -29.5 -38.9 -37.4 -38.5 -32.0 -42.1 -29.8 -25.0 -13.0 -7.6 2000 -8.9 -16.7 -25.4 -30.7 -32.9 -36.2 -34.7 -36.3 -36.8 -27.9 -12.5 -8.5 2001 -10.1 -14.2 -30.4 -31.4 -35.1 -33.7 -32.4 -46.0 -34.3 -27.7 -15.6 -6.9 2002 -6.5 -15.3 -24.1 -32.5 -30.5 -42.5 -42.8 -40.7 -31.6 -24.7 -15.4 -8.3 2003 - - - - - - - - - - - - 2004 - - - - - - - -43.0 -38.4 - - - 2005 - -14.7 - -32.4 -30.1 -35.7 -34.4 -37.0 - -24.3 -14.1 -4.4 2006 -5.6 - - - - - - - - - - - 2007 - - - - - - - - - - - - 2008 - - - - - - - - - - - - 2009 - - - - - - - - - - - -