These changes came from research I did to check the historical background behind Assembly Bill 385, which would abolish daylight saving time in California, and which has passed the CA Senate Appropriations Committee's suspense file. See: White JB. Bill letting California end Daylight Saving Time clears key committee. Sacramento Bee 2016-08-11. http://www.sacbee.com/news/politics-government/capitol-alert/article95116732... * NEWS, northamerica (CA): For America/Los_Angeles, correct spring-forward transition times from 02:00 to 02:01 in 1948, from 02:00 to 01:00 in 1950-1966. Correct the fall-back transition date for early 1949 from 1949-01-01 to 1949-01-16. --- NEWS | 7 +++++++ northamerica | 35 ++++++++++++++++++++++++++++++++--- 2 files changed, 39 insertions(+), 3 deletions(-) diff --git a/NEWS b/NEWS index ba26a49..a8479eb 100644 --- a/NEWS +++ b/NEWS @@ -7,6 +7,13 @@ Unreleased, experimental changes New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52. (Thanks to Tim Parenti.) + Changes affecting past time stamps + + For America/Los_Angeles, spring-forward transition times have been + corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in + 1950-1966. The fall-back transition date for early 1949 has been + corrected from 1949-01-01 to 1949-01-16. + Changes affecting code zic no longer generates binary files containing POSIX TZ-like diff --git a/northamerica b/northamerica index 6256f97..c9c2061 100644 --- a/northamerica +++ b/northamerica @@ -413,11 +413,40 @@ Zone America/Denver -6:59:56 - LMT 1883 Nov 18 12:00:04 # north of the Salmon River, and the towns of Burgdorf and Warren), # Nevada (except West Wendover), Oregon (except the northern 3/4 of # Malheur county), and Washington + +# From Paul Eggert (2016-08-19): +# In 1948 California had an electricity shortage. To save electricity, +# in early February PG&E changed power frequency from 60 to 59.5 Hz during +# daylight hours, causing electric clocks to lose six minutes per day. +# (This did not change legal time, and is not part of the data here.) +# See: Ross SA. An energy crisis from the past: Northern California in 1948. +# Working Paper No. 8, Institute of Governmental Studies, UC Berkeley, 1973-11. +# http://escholarship.org/uc/item/8x22k30c +# +# In another measure to save electricity, DST was instituted from 1948-03-14 +# at 02:01 to 1949-01-16 at 02:00, with the governor having the option to move +# the fallback transition earlier. See pages 3-4 of: +# http://clerk.assembly.ca.gov/sites/clerk.assembly.ca.gov/files/archive/Statu... +# Apparently the governor did not exercise the option. +# +# In response: +# +# Governor Warren received a torrent of objecting mail, and it is not too much +# to speculate that the objections to Daylight Saving Time were one important +# factor in the defeat of the Dewey-Warren Presidential ticket in California. +# -- Ross, p 25 +# +# Despite the controversy, in 1949 California voters approved Proposition 12, +# which established DST from April's last Sunday at 01:00 until September's +# last Sunday at 02:00. This was amended by 1962's Proposition 6, which changed +# the fall-back date to October's last Sunday. See: +# http://repository.uchastings.edu/cgi/viewcontent.cgi?article=1501&context=ca... +# http://repository.uchastings.edu/cgi/viewcontent.cgi?article=1636&context=ca... # # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER -Rule CA 1948 only - Mar 14 2:00 1:00 D -Rule CA 1949 only - Jan 1 2:00 0 S -Rule CA 1950 1966 - Apr lastSun 2:00 1:00 D +Rule CA 1948 only - Mar 14 2:01 1:00 D +Rule CA 1949 only - Jan 16 2:00 0 S +Rule CA 1950 1966 - Apr lastSun 1:00 1:00 D Rule CA 1950 1961 - Sep lastSun 2:00 0 S Rule CA 1962 1966 - Oct lastSun 2:00 0 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] -- 2.7.4