xref: /freebsd/contrib/tzdata/leapseconds (revision 868a59a7e296bed53dd7b986e79964eed8a59f71)
1# Allowance for leap seconds added to each time zone file.
2
3# This file is in the public domain.
4
5# This file is generated automatically from the data in the public-domain
6# leap-seconds.list file available from most NIST time servers.
7# If the URL <ftp://time.nist.gov/pub/leap-seconds.list> does not work,
8# you should be able to pick up leap-seconds.list from a secondary NIST server.
9# For more about leap-seconds.list, please see
10# The NTP Timescale and Leap Seconds
11# http://www.eecis.udel.edu/~mills/leap.html
12
13# The International Earth Rotation and Reference Systems Service
14# periodically uses leap seconds to keep UTC to within 0.9 s of UT1
15# (which measures the true angular orientation of the earth in space); see
16# Terry J Quinn, The BIPM and the accurate measure of time,
17# Proc IEEE 79, 7 (July 1991), 894-905 <http://dx.doi.org/10.1109/5.84965>.
18# There were no leap seconds before 1972, because the official mechanism
19# accounting for the discrepancy between atomic time and the earth's rotation
20# did not exist until the early 1970s.
21
22# The correction (+ or -) is made at the given time, so lines
23# will typically look like:
24#	Leap	YEAR	MON	DAY	23:59:60	+	R/S
25# or
26#	Leap	YEAR	MON	DAY	23:59:59	-	R/S
27
28# If the leapsecond is Rolling (R) the given time is local time.
29# If the leapsecond is Stationary (S) the given time is UTC.
30
31# Leap	YEAR	MONTH	DAY	HH:MM:SS	CORR	R/S
32Leap	1972	Jun	30	23:59:60	+	S
33Leap	1972	Dec	31	23:59:60	+	S
34Leap	1973	Dec	31	23:59:60	+	S
35Leap	1974	Dec	31	23:59:60	+	S
36Leap	1975	Dec	31	23:59:60	+	S
37Leap	1976	Dec	31	23:59:60	+	S
38Leap	1977	Dec	31	23:59:60	+	S
39Leap	1978	Dec	31	23:59:60	+	S
40Leap	1979	Dec	31	23:59:60	+	S
41Leap	1981	Jun	30	23:59:60	+	S
42Leap	1982	Jun	30	23:59:60	+	S
43Leap	1983	Jun	30	23:59:60	+	S
44Leap	1985	Jun	30	23:59:60	+	S
45Leap	1987	Dec	31	23:59:60	+	S
46Leap	1989	Dec	31	23:59:60	+	S
47Leap	1990	Dec	31	23:59:60	+	S
48Leap	1992	Jun	30	23:59:60	+	S
49Leap	1993	Jun	30	23:59:60	+	S
50Leap	1994	Jun	30	23:59:60	+	S
51Leap	1995	Dec	31	23:59:60	+	S
52Leap	1997	Jun	30	23:59:60	+	S
53Leap	1998	Dec	31	23:59:60	+	S
54Leap	2005	Dec	31	23:59:60	+	S
55Leap	2008	Dec	31	23:59:60	+	S
56Leap	2012	Jun	30	23:59:60	+	S
57Leap	2015	Jun	30	23:59:60	+	S
58
59#	Updated through IERS Bulletin C50
60#	File expires on:  28 June 2016
61