Schwerdtfeger 12Z temperature 1985 - -21.4 -27.0 -35.0 - -33.9 -47.2 -38.8 -35.6 -28.9 -19.7 -9.1 1986 -8.9 -17.7 -26.4 -29.9 -27.6 -35.7 -36.6 -41.5 -45.5 -30.0 -18.9 -8.8 1987 -7.3 -19.5 -32.7 -35.0 -32.7 -28.2 -35.6 -39.2 -36.4 -31.2 -21.2 -8.1 1988 -9.5 -20.8 -31.9 -31.1 -30.7 -30.9 -35.2 -28.3 -32.2 -24.2 -19.1 -8.0 1989 -8.0 -20.6 -26.0 -28.6 -35.0 -41.2 -36.5 -39.0 -36.0 -28.3 -15.3 -7.8 1990 -9.5 -20.3 -28.7 -32.0 -32.6 -37.6 -39.2 -40.9 -40.1 -33.2 -19.5 -7.2 1991 -9.3 -13.9 -30.4 -31.7 -34.2 -30.6 -38.6 -38.9 -30.6 -28.8 -17.8 -7.7 1992 -7.9 -21.8 -24.1 -35.6 -31.4 -35.8 -31.4 - - - - - 1993 - -20.3 -30.4 -31.6 -37.4 -32.4 -31.8 - - - -15.1 -9.9 1994 -7.7 -18.7 -30.6 -25.0 -39.2 -33.2 - - - - - - 1995 - - - - - - - - - - - - 1996 - -19.9 -31.0 -27.7 -37.7 -34.8 -38.3 -31.9 -33.8 -32.1 -18.0 -9.3 1997 -10.5 -22.4 -33.0 -36.9 -32.5 -33.4 -38.9 -42.2 -35.8 -24.9 -13.2 -10.1 1998 -11.5 -16.2 -29.9 -38.7 -34.5 -28.2 -38.6 -36.9 -41.3 -29.0 -20.1 -11.3 1999 -9.4 -22.7 -32.4 -38.3 -37.5 -38.4 -31.0 -42.2 -30.7 -28.2 -16.3 -10.8 2000 -11.7 -20.7 -27.0 -29.6 -33.3 -36.0 -33.9 -36.7 -38.5 -32.3 -14.6 -11.7 2001 -13.5 -18.2 -33.1 -32.3 -36.1 -32.7 -33.8 -46.9 -34.8 -31.5 -19.2 -9.8 2002 -9.7 -18.0 -25.2 -32.3 -30.8 -41.9 -43.9 -40.2 -32.8 -28.7 -19.3 -10.9 2003 -9.1 - - - - - -31.2 - - - - - 2004 - - - - - - - - - - - - 2005 - -20.2 -29.8 -33.8 -30.1 -33.7 -35.1 -38.2 -37.1 -27.0 -18.0 -8.3 2006 -11.2 - - - - - - - - - - - 2007 - - - - - - - - - - - - 2008 - - - - - - - - - - - - 2009 - - - - - - - - - - - -