Casey 12Z 500hPa temperature 1957 - - - -33.1 -35.2 -34.2 -36.6 -37.5 -38.5 -33.7 -33.7 -29.8 1958 -29.2 -32.7 -33.9 -35.3 -32.8 -37.7 -36.8 -39.4 -39.9 -37.9 -34.9 -32.0 1959 -30.8 -30.7 -30.4 -32.9 -35.9 -38.6 -39.8 -37.7 -40.6 -34.7 -36.0 -29.1 1960 -29.6 -30.0 -35.4 -36.2 -36.5 -37.8 -40.0 -38.4 -38.8 -38.2 -34.0 -30.6 1961 -29.2 -28.9 -33.3 -33.5 -36.4 -34.6 - -36.7 - - -32.2 -34.1 1962 -33.1 -32.0 -34.6 -34.3 -37.0 -36.7 -39.7 -38.4 -38.4 -37.2 -33.0 -33.1 1963 - - - - - - - - - - - - 1964 - -30.6 -33.5 - - - - - -40.4 -37.1 -33.4 -29.0 1965 -30.4 -30.8 -32.7 - - - - - - - - - 1966 -30.1 -28.9 -27.8 - - - - - - - - - 1967 - - - - - - - - - - - - 1968 - - - - - - - - - -36.5 -33.5 -31.6 1969 -30.2 -32.1 - - - - - - - -35.7 -34.7 -31.2 1970 -28.8 -31.9 -31.2 - - - - - - -37.7 -32.8 -29.1 1971 -27.7 -28.7 -36.2 - - - - - - -37.4 -33.0 -29.2 1972 -28.4 -32.1 -33.5 - - - - - - - -34.5 -29.5 1973 -29.5 -33.0 -33.3 - - - - - - -35.4 -33.2 -31.7 1974 -29.9 -30.3 -35.0 - - - - - - -34.2 -33.2 -29.7 1975 -27.8 -29.7 -30.1 - - - - - - -35.6 -34.3 -31.5 1976 -28.4 -30.2 -31.5 - - - - - - -37.4 -33.3 -28.3 1977 -27.5 -29.1 -33.2 - - - - - - -40.2 -34.7 - 1978 - - - - - - - - - - - - 1979 - - - - - - - - - - - - 1980 - - - - - - - - - - - - 1981 - - - - - - - - - - - - 1982 - - - - - - - - - - - - 1983 - - - - - - - - - - - - 1984 - - - - - - - - - - - - 1985 - - - - - - - - - - - - 1986 - - - - - - - - - - - - 1987 - - - - - - - - - - - - 1988 - - - - - -34.3 -37.2 -36.3 -34.4 -35.2 -33.9 -32.1 1989 -29.5 -30.3 -33.4 -33.6 -37.7 -36.7 -36.4 -37.2 -36.2 -35.0 -35.0 -25.4 1990 -27.7 -29.5 -31.5 -30.8 -33.8 -37.4 -35.0 -38.5 -39.2 -36.2 -32.5 -28.3 1991 -31.6 -28.9 -30.0 -33.6 -35.1 -33.0 -32.3 -36.1 -38.3 -37.0 -30.4 -31.1 1992 -28.5 -30.0 -30.1 -36.2 -33.7 -32.2 -36.5 -36.8 -39.4 -36.3 -33.0 -31.9 1993 -29.2 -30.8 -32.0 -36.5 -38.3 -37.6 -37.2 -38.9 -37.7 -37.1 -35.0 -32.8 1994 -28.8 -31.0 -32.9 -36.5 -35.1 -32.2 -35.9 -38.3 -35.2 -37.6 -33.2 -33.0 1995 -31.0 -31.1 -31.3 -34.5 -35.2 -36.3 -31.7 -36.4 -38.5 -36.4 -32.0 -29.4 1996 -29.3 -30.1 -33.2 -33.3 -37.8 -33.2 -35.1 -34.2 -34.7 -36.4 -33.5 -31.4 1997 -30.8 -31.3 -31.5 -35.6 -34.8 -34.9 -39.5 -38.8 -39.4 -37.3 -31.9 -30.2 1998 -31.0 -29.6 -32.7 -35.4 -38.2 -36.6 -37.5 -35.3 -35.8 -37.2 -32.3 -33.1 1999 -32.2 -30.7 -32.3 -36.8 -36.5 -35.4 -38.5 -37.8 -37.9 -36.1 -33.5 -32.4 2000 -29.7 -30.4 -33.2 -32.1 -36.8 -34.0 -36.5 -37.2 -35.1 -38.6 -30.5 -29.7 2001 -28.6 -26.3 -30.9 -36.8 -35.1 -36.0 -36.6 -40.1 -38.2 -36.3 -33.6 -28.5 2002 -30.7 -29.6 -29.1 -32.0 -30.4 -33.9 -34.8 -37.0 -37.8 -34.2 -33.7 -28.4 2003 -27.6 -25.3 -31.3 -35.1 -35.5 -34.7 -37.5 -37.5 -36.8 -37.9 -31.6 -28.9 2004 -27.9 -30.7 -32.1 -34.4 -34.8 -36.1 - - - - - - 2005 - - - - - - - - - - - -27.0 2006 -30.1 -31.6 -33.1 -33.7 -39.0 -38.6 -37.0 -37.4 -34.4 -35.9 -32.8 -31.1 2007 -28.2 -30.8 -32.7 -31.9 -31.4 -34.0 -34.6 -35.3 -37.1 -35.9 -31.8 -32.5 2008 -31.1 -29.8 -33.1 -33.4 -34.2 -38.5 -37.3 -38.7 -38.7 -37.8 -31.9 -30.0 2009 -30.2 -29.2 -31.4 -33.9 -36.0 -36.6 -32.6 -37.3 -35.3 -36.9 -32.6 -31.9 2010 -28.3 -29.8 -30.2 -34.2 -37.3 -36.7 -38.7 -38.8 -35.6 -36.8 -33.8 -29.4 2011 -27.7 -33.1 -30.1 -31.5 - - - - - - -33.5 -33.3 2012 -30.1 -31.2 -32.9 -32.4 -36.9 -36.0 -40.0 -38.0 -39.0 -34.3 -31.8 -31.0 2013 -28.3 -29.3 -33.9 -35.2 -35.6 -35.4 -37.2 -37.0 -32.2 -36.5 -30.0 -31.2 2014 -28.5 -31.3 -34.0 -36.7 -33.4 -36.2 -37.3 -39.1 -36.4 -36.4 -30.0 -31.8 2015 -29.1 -31.2 -32.6 -34.8 -37.7 -35.5 -37.3 -36.7 -38.3 -38.7 -32.3 -30.3 2016 -30.5 -33.3 -33.0 -33.9 -34.0 -37.8 -37.2 -37.7 -38.4 -34.9 -32.9 -30.9 2017 -29.2 -29.5 -33.2 - - -37.0 -35.3 -38.8 -38.5 -36.5 -32.7 -30.7 2018 -29.8 -29.7 -33.6 -32.8 -37.1 -36.2 -35.8 -37.5 -38.8 -37.9 -35.1 -32.2 2019 -31.1 -29.4 -33.1 -32.7 -35.8 -35.6 -34.4 -35.7 -37.5 -35.0 -31.0 -29.3 2020 -27.4 -30.3 -33.3 -31.3 -34.1 -36.7 -33.5 -35.9 -34.8 -33.2 -32.4 -31.4 2021 -31.5 -30.3 -31.2 -33.9 -36.2 -39.1 -36.4 -35.9 -36.8 -33.8 -35.1 -28.4 2022 -31.4 -31.2 -32.8 -34.9 -33.7 -32.3 -36.4 -36.3 -36.7 -35.5 -34.2 -31.2 2023 -31.6 -29.1 -29.6 -34.4 -37.1 -35.6 -39.0 -40.0 -35.2 -36.6 -33.6 -29.8 2024 -29.2 -31.9 -32.2 -34.6 - - - - - - - -