Dear IANA TZ,

  Since the last time change Chile has been in GMT-3 (i.e. Chile is right now in GMT-3).

  Chile is going to GMT-4 in May,14th midnight and returning to GMT-3 in August, 13th midnight.
  That means clocks will go back 1 hour at 00:00 May 15th (jumping back to May 14th); and will go forward by 1 hour on 00:00, August 14th.

  In tzdata2016c I can see this new rules for Chile:
# Rule  NAME     FROM    TO    TYPE  IN    ON      AT     SAVE   LETTER/S
Rule    Chile    2016    max    -    May   Sun>=9  3:00u  0      -
Rule    Chile    2016    max    -    Aug   Sun>=9  4:00u  1:00   S

  And I can see this Chile zone definition:
# Zone    NAME        GMTOFF    RULES    FORMAT    [UNTIL]
Zone America/Santiago    -4:42:46 -    LMT    1890
            -4:42:46 -    SMT    1910 Jan 10 # Santiago Mean Time
            -5:00    -    CLT    1916 Jul  1 # Chile Time
            -4:42:46 -    SMT    1918 Sep 10
            -4:00    -    CLT    1919 Jul  1
            -4:42:46 -    SMT    1927 Sep  1
            -5:00    Chile    CL%sT    1932 Sep  1
            -4:00    -    CLT    1942 Jun  1
            -5:00    -    CLT    1942 Aug  1
            -4:00    -    CLT    1946 Jul 15
            -4:00    1:00    CLST    1946 Sep  1 # central Chile
            -4:00    -    CLT    1947 Apr  1
            -5:00    -    CLT    1947 May 21 23:00
            -4:00    Chile    CL%sT

  But with these two information I'm not sure that in the midnight of May, 14th this tzdata2016c will change the TZ of Chile from GMT-3 to GMT-4.

  Can you please explain me how these structures in tzdata2016c work to accomplish the necessary TZ change in Chile.


  Thank you very much, best regards.

  Luis