Contiguous U.S. CEI (All Steps Combined) Warm Season (April-September) 1910-2018
Date Actual Percent
1910 19.82
1911 22.54
1912 25.48
1913 15.90
1914 17.90
1915 27.96
1916 18.44
1917 26.48
1918 16.66
1919 20.70
1920 23.44
1921 20.02
1922 9.62
1923 17.62
1924 31.98
1925 21.08
1926 16.16
1927 22.28
1928 23.40
1929 13.66
1930 17.14
1931 23.42
1932 9.56
1933 16.42
1934 37.80
1935 10.06
1936 32.16
1937 13.90
1938 11.04
1939 15.60
1940 21.26
1941 35.54
1942 14.74
1943 9.88
1944 12.48
1945 22.50
1946 8.82
1947 7.96
1948 17.56
1949 11.48
1950 28.86
1951 22.94
1952 14.10
1953 19.74
1954 28.24
1955 19.60
1956 21.82
1957 14.12
1958 15.18
1959 9.84
1960 10.36
1961 20.00
1962 7.02
1963 19.52
1964 16.54
1965 25.90
1966 13.70
1967 21.76
1968 16.78
1969 6.84
1970 7.44
1971 9.74
1972 9.02
1973 19.12
1974 14.38
1975 23.60
1976 21.92
1977 16.90
1978 13.54
1979 16.52
1980 16.72
1981 12.26
1982 13.70
1983 22.12
1984 16.38
1985 9.34
1986 13.82
1987 17.32
1988 22.80
1989 18.94
1990 13.42
1991 22.08
1992 31.06
1993 27.28
1994 16.40
1995 19.66
1996 17.94
1997 21.94
1998 33.28
1999 16.28
2000 21.06
2001 21.28
2002 23.34
2003 19.72
2004 15.26
2005 16.08
2006 22.78
2007 30.82
2008 14.90
2009 16.38
2010 34.90
2011 35.52
2012 37.90
2013 21.90
2014 17.36
2015 29.84
2016 26.84
2017 20.64
2018 36.96