leapseconds
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 # NIST format leap-seconds.list file, which can be copied from 7 # <ftp://ftp.nist.gov/pub/time/leap-seconds.list> 8 # or <ftp://ftp.boulder.nist.gov/pub/time/leap-seconds.list>. 9 # The NIST file is used instead of its IERS upstream counterpart 10 # <https://hpiers.obspm.fr/iers/bul/bulc/ntp/leap-seconds.list> 11 # because under US law the NIST file is public domain 12 # whereas the IERS file's copyright and license status is unclear. 13 # For more about leap-seconds.list, please see 14 # The NTP Timescale and Leap Seconds 15 # <https://www.eecis.udel.edu/~mills/leap.html>. 16 17 # The rules for leap seconds are specified in Annex 1 (Time scales) of: 18 # Standard-frequency and time-signal emissions. 19 # International Telecommunication Union - Radiocommunication Sector 20 # (ITU-R) Recommendation TF.460-6 (02/2002) 21 # <https://www.itu.int/rec/R-REC-TF.460-6-200202-I/>. 22 # The International Earth Rotation and Reference Systems Service (IERS) 23 # periodically uses leap seconds to keep UTC to within 0.9 s of UT1 24 # (a proxy for Earth's angle in space as measured by astronomers) 25 # and publishes leap second data in a copyrighted file 26 # <https://hpiers.obspm.fr/iers/bul/bulc/Leap_Second.dat>. 27 # See: Levine J. Coordinated Universal Time and the leap second. 28 # URSI Radio Sci Bull. 2016;89(4):30-6. doi:10.23919/URSIRSB.2016.7909995 29 # <https://ieeexplore.ieee.org/document/7909995>. 30 31 # There were no leap seconds before 1972, as no official mechanism 32 # accounted for the discrepancy between atomic time (TAI) and the earth's 33 # rotation. The first ("1 Jan 1972") data line in leap-seconds.list 34 # does not denote a leap second; it denotes the start of the current definition 35 # of UTC. 36 37 # All leap-seconds are Stationary (S) at the given UTC time. 38 # The correction (+ or -) is made at the given time, so in the unlikely 39 # event of a negative leap second, a line would look like this: 40 # Leap YEAR MON DAY 23:59:59 - S 41 # Typical lines look like this: 42 # Leap YEAR MON DAY 23:59:60 + S 43 Leap 1972 Jun 30 23:59:60 + S 44 Leap 1972 Dec 31 23:59:60 + S 45 Leap 1973 Dec 31 23:59:60 + S 46 Leap 1974 Dec 31 23:59:60 + S 47 Leap 1975 Dec 31 23:59:60 + S 48 Leap 1976 Dec 31 23:59:60 + S 49 Leap 1977 Dec 31 23:59:60 + S 50 Leap 1978 Dec 31 23:59:60 + S 51 Leap 1979 Dec 31 23:59:60 + S 52 Leap 1981 Jun 30 23:59:60 + S 53 Leap 1982 Jun 30 23:59:60 + S 54 Leap 1983 Jun 30 23:59:60 + S 55 Leap 1985 Jun 30 23:59:60 + S 56 Leap 1987 Dec 31 23:59:60 + S 57 Leap 1989 Dec 31 23:59:60 + S 58 Leap 1990 Dec 31 23:59:60 + S 59 Leap 1992 Jun 30 23:59:60 + S 60 Leap 1993 Jun 30 23:59:60 + S 61 Leap 1994 Jun 30 23:59:60 + S 62 Leap 1995 Dec 31 23:59:60 + S 63 Leap 1997 Jun 30 23:59:60 + S 64 Leap 1998 Dec 31 23:59:60 + S 65 Leap 2005 Dec 31 23:59:60 + S 66 Leap 2008 Dec 31 23:59:60 + S 67 Leap 2012 Jun 30 23:59:60 + S 68 Leap 2015 Jun 30 23:59:60 + S 69 Leap 2016 Dec 31 23:59:60 + S 70 71 # UTC timestamp when this leap second list expires. 72 # Any additional leap seconds will come after this. 73 # This Expires line is commented out for now, 74 # so that pre-2020a zic implementations do not reject this file. 75 #Expires 2023 Jun 28 00:00:00 76 77 # POSIX timestamps for the data in this file: 78 #updated 1467936000 (2016-07-08 00:00:00 UTC) 79 #expires 1687910400 (2023-06-28 00:00:00 UTC) 80 81 # Updated through IERS Bulletin C64 82 # File expires on: 28 June 2023