[tz] [PROPOSED] Cite US DST legislation
Paul Eggert
eggert at cs.ucla.edu
Tue Jun 4 07:08:30 UTC 2019
* northamerica: Cite all the US federal DST legislation.
(US): Adjust table to match the legislation more closely.
This does not affect the TZif output files.
---
northamerica | 26 ++++++++++++++++++++------
1 file changed, 20 insertions(+), 6 deletions(-)
diff --git a/northamerica b/northamerica
index 65827ec..52898de 100644
--- a/northamerica
+++ b/northamerica
@@ -93,10 +93,24 @@
# was the first nationwide legal time standard, and apparently
# time was just called "Standard Time" or "Daylight Saving Time".
-# From Arthur David Olson:
-# US Daylight Saving Time ended on the last Sunday of *October* in 1974.
-# See, for example, the front page of the Saturday, 1974-10-26
-# and Sunday, 1974-10-27 editions of the Washington Post.
+# From Paul Eggert (2019-06-04):
+# Here is the legal basis for the US federal rules.
+# * Public Law 65-107 (1918-03-19) implemented standard and daylight saving
+# time for the first time across the US, springing forward on March's last
+# Sunday and falling back on October's last Sunday.
+# * Public Law 66-40 (1919-08-20) repealed DST on October 1919's last Sunday.
+# * Public Law 77-403 (1942-01-20) started wartime DST on 1942-02-09.
+# * Public Law 79-187 (1945-09-25) ended wartime DST on 1945-09-30.
+# * Public Law 89-387 (1966-04-13) reinstituted a national standard for DST,
+# from April's last Sunday to October's last Sunday, effective 1967.
+# * Public Law 93-182 (1973-12-15) moved the 1974 spring-forward to 01-06.
+# * Public Law 94-434 (1974-10-05) moved the 1975 spring-forward to
+# February's last Sunday.
+# * Public Law 99-359 (1986-07-08) moved the spring-forward to April's first
+# Sunday.
+# * Public Law 109-50 (2005-08-08), effective 2007, moved the spring-forward
+# to March's second Sunday and the fall-back to November's first Sunday.
+# All transitions are at 02:00 local time.
# From Arthur David Olson:
# Before the Uniform Time Act of 1966 took effect in 1967, observance of
@@ -152,11 +166,11 @@ Rule US 1918 1919 - Mar lastSun 2:00 1:00 D
Rule US 1918 1919 - Oct lastSun 2:00 0 S
Rule US 1942 only - Feb 9 2:00 1:00 W # War
Rule US 1945 only - Aug 14 23:00u 1:00 P # Peace
-Rule US 1945 only - Sep lastSun 2:00 0 S
+Rule US 1945 only - Sep 30 2:00 0 S
Rule US 1967 2006 - Oct lastSun 2:00 0 S
Rule US 1967 1973 - Apr lastSun 2:00 1:00 D
Rule US 1974 only - Jan 6 2:00 1:00 D
-Rule US 1975 only - Feb 23 2:00 1:00 D
+Rule US 1975 only - Feb lastSun 2:00 1:00 D
Rule US 1976 1986 - Apr lastSun 2:00 1:00 D
Rule US 1987 2006 - Apr Sun>=1 2:00 1:00 D
Rule US 2007 max - Mar Sun>=8 2:00 1:00 D
--
2.21.0
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