I have to report an error in zone America/Kentucky/Louisville zdump gives zdump -V -c 1945,1950 America/Kentucky/Louisville America/Kentucky/Louisville  Tue Aug 14 22:59:59 1945 UT = Tue Aug 14 17:59:59 1945 CWT isdst=1 gmtoff=-18000 America/Kentucky/Louisville  Tue Aug 14 23:00:00 1945 UT = Tue Aug 14 18:00:00 1945 CPT isdst=1 gmtoff=-18000 America/Kentucky/Louisville  Sun Sep 30 06:59:59 1945 UT = Sun Sep 30 01:59:59 1945 CPT isdst=1 gmtoff=-18000 America/Kentucky/Louisville  Sun Sep 30 07:00:00 1945 UT = Sun Sep 30 01:00:00 1945 CST isdst=0 gmtoff=-21600 America/Kentucky/Louisville  Tue Jan  1 05:59:59 1946 UT = Mon Dec 31 23:59:59 1945 CST isdst=0 gmtoff=-21600 America/Kentucky/Louisville  Tue Jan  1 06:00:00 1946 UT = Tue Jan  1 01:00:00 1946 CDT isdst=1 gmtoff=-18000 America/Kentucky/Louisville  Sun Jun  2 06:59:59 1946 UT = Sun Jun  2 01:59:59 1946 CDT isdst=1 gmtoff=-18000 America/Kentucky/Louisville  Sun Jun  2 07:00:00 1946 UT = Sun Jun  2 01:00:00 1946 CST isdst=0 gmtoff=-21600 America/Kentucky/Louisville  Sun Apr 27 07:59:59 1947 UT = Sun Apr 27 01:59:59 1947 CST isdst=0 gmtoff=-21600 America/Kentucky/Louisville  Sun Apr 27 08:00:00 1947 UT = Sun Apr 27 03:00:00 1947 CDT isdst=1 gmtoff=-18000 with a strange transition CST to CDT on 1 January 1946. I have searched Louisville newspaper archives and find no report of such a clock change around New Year 1946. I find however the begin of CDT for 28 April 1946, and the switch back to CST on 2 June 1946. Shanks also has the transition on 28 April 1946. The cause I thnk is the strange formulation of Louisville rules # This also includes Clark, Floyd, and Harrison counties in Indiana. # Rule  NAME    FROM    TO      TYPE    IN      ON      AT SAVE    LETTER Rule Louisville 1921    only    -       May     1       2:00 1:00    D Rule Louisville 1921    only    -       Sep     1       2:00 0       S Rule Louisville 1941    1961    -       Apr     lastSun 2:00 1:00    D Rule Louisville 1941    only    -       Sep     lastSun 2:00 0       S Rule Louisville 1946    only    -       Jun     2       2:00 0       S Rule Louisville 1950    1955    -       Sep     lastSun 2:00 0       S Rule Louisville 1956    1960    -       Oct     lastSun 2:00 0       S # Zone  NAME            STDOFF  RULES   FORMAT  [UNTIL] Zone America/Kentucky/Louisville -5:43:02 -     LMT     1883 Nov 18 12:16:58                         -6:00   US      C%sT    1921                         -6:00 Louisville C%sT   1942                         -6:00   US      C%sT    1946                         -6:00 Louisville C%sT   1961 Jul 23 2:00                         -5:00   -       EST     1968                         -5:00   US      E%sT    1974 Jan  6 2:00                         -6:00   1:00    CDT     1974 Oct 27 2:00                         -5:00   US      E%sT I attach a newspaper article describing the swith on 28 April.