xref: /freebsd-10.3-release/contrib/tzdata/leapseconds

# @(#)leapseconds	7.16

# Allowance for leapseconds added to each timezone file.

# The International Earth Rotation Service periodically uses leap seconds
# to keep UTC to within 0.9 s of UT1
# (which measures the true angular orientation of the earth in space); see
# Terry J Quinn, The BIPM and the accurate measure of time,
# Proc IEEE 79, 7 (July 1991), 894-905.
# There were no leap seconds before 1972, because the official mechanism
# accounting for the discrepancy between atomic time and the earth's rotation
# did not exist until the early 1970s.

# The correction (+ or -) is made at the given time, so lines
# will typically look like:
#	Leap	YEAR	MON	DAY	23:59:60	+	R/S
# or
#	Leap	YEAR	MON	DAY	23:59:59	-	R/S

# If the leapsecond is Rolling (R) the given time is local time
# If the leapsecond is Stationary (S) the given time is UTC

# Leap	YEAR	MONTH	DAY	HH:MM:SS	CORR	R/S
Leap	1972	Jun	30	23:59:60	+	S
Leap	1972	Dec	31	23:59:60	+	S
Leap	1973	Dec	31	23:59:60	+	S
Leap	1974	Dec	31	23:59:60	+	S
Leap	1975	Dec	31	23:59:60	+	S
Leap	1976	Dec	31	23:59:60	+	S
Leap	1977	Dec	31	23:59:60	+	S
Leap	1978	Dec	31	23:59:60	+	S
Leap	1979	Dec	31	23:59:60	+	S
Leap	1981	Jun	30	23:59:60	+	S
Leap	1982	Jun	30	23:59:60	+	S
Leap	1983	Jun	30	23:59:60	+	S
Leap	1985	Jun	30	23:59:60	+	S
Leap	1987	Dec	31	23:59:60	+	S
Leap	1989	Dec	31	23:59:60	+	S
Leap	1990	Dec	31	23:59:60	+	S
Leap	1992	Jun	30	23:59:60	+	S
Leap	1993	Jun	30	23:59:60	+	S
Leap	1994	Jun	30	23:59:60	+	S
Leap	1995	Dec	31	23:59:60	+	S
Leap	1997	Jun	30	23:59:60	+	S
Leap	1998	Dec	31	23:59:60	+	S

# 		INTERNATIONAL EARTH ROTATION SERVICE (IERS)
# 		SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE
# 
# SERVICE DE LA ROTATION TERRESTRE
# OBSERVATOIRE DE PARIS
# 61, Av. de l'Observatoire 75014 PARIS (France)
# Tel.      : 33 (0) 1 40 51 22 26
# FAX       : 33 (0) 1 40 51 22 91
# Internet  : iers@obspm.fr
# 
# 				 		Paris, 1 July 2003
# 
# 						Bulletin C 26
# 
# 						To authorities responsible
# 						for the measurement and
# 						distribution of time
# 
# 			INFORMATION ON UTC - TAI
# 
# NO positive leap second will be introduced at the end of December 2003.
# The difference between UTC and the International Atomic Time TAI is:
# 		
# 	from 1999 January 1, 0h UTC, until further notice: UTC-TAI = -32 s
# 
# Leap seconds can be introduced in UTC at the end of the months of December
# or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every
# six months, either to announce a time step in UTC, or to confirm that there
# will be no time step at the next possible date.
# 
# 					Daniel GAMBIS
# 					Director
# 					Earth Orientation Center of IERS