I asked on the net about Mexico's DST rule change this year; the most authoritative-sounding response I got was from Kevin Pitts, so I've included his version in the patch proposed below. Further corrections may be needed, since there seems to be some confusion about the changes; e.g. in http://mexico-travel.com/mex_eng.html, Mexico's Ministry of Tourism claims that Mexico switched to US style DST rules way back in spring 1994. =================================================================== RCS file: RCS/northamerica,v retrieving revision 1995.13 retrieving revision 1995.13.1.1 diff -c -r1995.13 -r1995.13.1.1 *** northamerica 1995/12/21 17:18:31 1995.13 --- northamerica 1996/02/10 04:40:26 1995.13.1.1 *************** *** 852,857 **** --- 852,866 ---- # Shanks also says there are four zones, but disagrees about the fourth. # Instead of GMT-6 with DST, he says there's GMT-8 without DST. + # From Paul Eggert (1996-02-07): + # Today in news:4f90v4$g6g@news.internet.com.mx, Kevin Pitts + # <bravo2@internet.com.mx> wrote that Mexico will use Horario de Verano (DST) + # starting this year with the same rules as the US, and gave FIDE as a source. + # (FIDE is a private organization that promotes efficient electrical use.) + # On 1996-02-02 Mario Camou wrote that the transition times are Apr Sun>=1 + # 0:00 and Nov 1 0:00 but also wrote ``The DST-out date looks a bit fishy''. + # Go with Pitts after 1996, and with Shanks before that. + # From Shanks (1991): # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Mexico 1922 only - Jan 1 0:00 0 S *************** *** 863,868 **** --- 872,880 ---- Rule Mexico 1944 only - May 1 0:00 0 S Rule Mexico 1950 only - Feb 12 0:00 1:00 D Rule Mexico 1950 only - Jul 30 0:00 0 S + Rule Mexico 1996 max - Apr Sun>=1 2:00 1:00 D + Rule Mexico 1996 max - Oct lastSun 2:00 0 S + # Rule BajaN 1950 1966 - Apr lastSun 2:00 1:00 D Rule BajaN 1950 1961 - Sep lastSun 2:00 0 S Rule BajaN 1961 1966 - Oct lastSun 2:00 0 S *************** *** 883,902 **** -6:00 - CST 1942 Apr -7:00 - MST 1949 Jan 14 -8:00 - PST 1970 ! -7:00 - MST Zone America/Tijuana -7:48:04 - LMT 1922 Jan 1 0:11:56 -8:00 - PST 1927 Jun 10 23:00 -7:00 - MST 1930 Nov 16 -8:00 - PST 1942 Apr -7:00 - MST 1949 Jan 14 -8:00 BajaN P%sT 1967 Apr lastSun 2:00 ! -8:00 US P%sT Zone America/Ensenada -7:46:28 - LMT 1922 Jan 1 0:13:32 -8:00 - PST 1927 Jun 10 23:00 -7:00 - MST 1930 Nov 16 -8:00 - PST 1942 Apr -7:00 - MST 1949 Jan 14 ! -8:00 - PST # # Revillagigedo Is # no information --- 895,916 ---- -6:00 - CST 1942 Apr -7:00 - MST 1949 Jan 14 -8:00 - PST 1970 ! -7:00 Mexico M%sT Zone America/Tijuana -7:48:04 - LMT 1922 Jan 1 0:11:56 -8:00 - PST 1927 Jun 10 23:00 -7:00 - MST 1930 Nov 16 -8:00 - PST 1942 Apr -7:00 - MST 1949 Jan 14 -8:00 BajaN P%sT 1967 Apr lastSun 2:00 ! -8:00 US P%sT 1996 ! -8:00 Mexico P%sT Zone America/Ensenada -7:46:28 - LMT 1922 Jan 1 0:13:32 -8:00 - PST 1927 Jun 10 23:00 -7:00 - MST 1930 Nov 16 -8:00 - PST 1942 Apr -7:00 - MST 1949 Jan 14 ! -8:00 - PST 1996 ! -8:00 Mexico P%sT # # Revillagigedo Is # no information