Schwerdtfeger temperature 1985 - -19.1 -25.7 -35.1 - -34.6 -47.2 -39.2 -35.7 -27.5 -17.2 -7.6 1986 -7.7 -15.6 -26.1 -30.2 -27.4 -35.6 -37.3 -41.2 -44.6 -28.3 -16.6 -7.6 1987 -5.5 -17.7 -32.3 -34.6 -33.2 -28.3 -34.8 -39.4 -36.3 -28.7 -18.5 -6.4 1988 -7.5 -18.1 -30.9 -30.9 -31.1 -32.5 -34.8 -28.2 -31.6 -22.5 -16.8 -6.7 1989 -6.5 -18.0 -26.0 -28.5 -34.9 -41.3 -36.7 -38.7 -35.3 -26.8 -13.6 -6.2 1990 -7.2 -18.4 -28.3 -31.2 -33.2 -37.4 -38.5 - -39.8 -30.3 -16.3 -5.8 1991 -7.5 -13.0 -29.5 -31.3 -33.8 -30.2 -38.9 -38.6 -30.8 -27.1 -15.7 -6.0 1992 -6.2 -18.8 -23.7 -36.5 -31.6 -36.0 -31.2 - - - - - 1993 - -18.2 -29.7 -31.3 -37.9 -32.5 -31.9 - - - -13.4 -7.4 1994 -5.7 -16.6 -29.5 -25.4 -39.3 -32.7 -32.8 - - - - - 1995 - - - - - - - - - - - - 1996 - -17.7 -30.2 -28.3 -36.7 -35.2 -38.2 -33.0 -33.0 -30.5 -16.1 -7.5 1997 -9.1 -20.5 -32.1 -36.7 -32.9 -33.2 -38.8 -42.3 -35.6 -23.2 -11.9 -8.6 1998 -9.9 -14.7 -28.4 -38.9 -34.9 -27.8 -38.6 -37.5 -40.7 -27.3 -17.8 -8.8 1999 -8.2 -19.5 -31.0 -38.7 -37.6 -38.4 -31.9 -42.0 -30.3 -26.4 -14.5 -8.8 2000 -10.2 -18.5 -26.4 -30.5 -33.0 -36.1 -34.1 -36.3 -37.6 -29.8 -13.3 -9.7 2001 -11.7 -16.2 -31.7 -31.6 -35.5 -33.4 -33.2 -46.4 -34.5 -29.4 -17.1 -8.0 2002 -8.0 -16.6 -24.8 -32.3 -31.1 -42.1 -43.4 -40.3 -32.1 -26.6 -16.9 -9.4 2003 - - - - - - -32.3 - - - - - 2004 - - - - - - - - - - - - 2005 - -17.5 -28.8 -33.3 -30.2 -35.0 -34.6 -37.6 -35.8 -25.6 -15.9 -6.0 2006 -8.1 - - - - - - - - - - - 2007 - - - - - - - - - - - - 2008 - - - - - - - - - - - - 2009 - - - - - - - - - - - -