Schwerdtfeger 06Z temperature 1985 - -16.6 -25.4 -35.7 -34.1 -34.4 -47.8 -39.4 -35.5 -26.4 -14.8 -5.9 1986 -6.1 -13.7 -26.2 -30.3 -27.6 -35.1 -36.4 -40.8 -44.4 -27.0 -14.6 -6.0 1987 -3.5 -15.9 -31.4 -34.5 -33.9 -28.5 -34.1 -39.0 -36.1 -26.9 -15.8 -4.6 1988 -5.8 -15.8 -29.9 -30.8 -31.4 -32.3 -35.0 -28.4 -32.1 -21.1 -14.8 -5.4 1989 -4.8 -15.5 -25.7 -29.0 -35.4 -41.5 -37.1 -39.1 -35.1 -25.0 -12.5 -4.6 1990 -4.9 -15.8 -27.6 -31.4 -32.9 -38.0 -37.7 - -39.6 -28.3 -13.5 -4.6 1991 -5.6 -11.8 -28.3 -31.0 -33.0 -30.5 -38.3 -38.3 -31.5 -25.3 -13.3 -4.1 1992 -4.9 -16.3 -23.0 -37.3 -31.9 -35.5 -31.8 - - - - - 1993 - -16.1 -28.4 -30.7 -37.6 -32.5 -31.4 - - - -11.5 -5.0 1994 -3.3 -14.0 -28.3 -25.8 -39.1 -32.0 -31.7 - - - - - 1995 - - - - - - - - - - - - 1996 - -14.9 -29.0 -28.6 -37.0 -34.4 -38.0 -33.9 -33.3 -28.9 -14.3 -5.1 1997 -7.5 -18.4 -30.8 -37.0 -33.8 -32.6 -38.4 -43.3 -34.9 -21.6 -10.0 -7.2 1998 -8.2 -13.6 -27.2 -39.1 -35.3 -27.5 -38.4 -37.6 -40.0 -25.4 -15.2 -6.2 1999 -6.6 -16.8 -29.6 -38.1 -37.5 -38.2 -32.6 -42.0 -29.8 -24.6 -13.0 -6.6 2000 -8.4 -16.2 -25.6 -30.9 -32.7 -36.4 -33.8 -36.0 -36.8 -27.1 -11.8 -6.9 2001 -9.7 -14.8 -31.0 -30.8 -35.2 -34.0 -33.8 -45.6 -34.5 -27.2 -14.4 -5.6 2002 -6.2 -14.8 -24.6 -32.5 -31.7 -41.8 -43.5 -40.4 -31.7 -25.3 -14.9 -7.8 2003 - - - -33.7 - - -32.5 - - - - - 2004 - - - - - - - - - - - - 2005 - -14.8 - -34.4 - - -35.4 -37.6 -35.2 -24.2 -13.0 -4.3 2006 -5.3 - - - - - - - - - - - 2007 - - - - - - - - - - - - 2008 - - - - - - - - - - - - 2009 - - - - - - - - - - - -