Hong Kong Time (abbreviation: HKT ; Chinese: 香港時間) is the
time in Hong Kong, observed at UTC+08:00 all year round. The Hong
Kong Observatory is the official timekeeper of the
Hong Kong Time.
1 Time standards
3 Daylight Saving
4 See also
6 External links
In Hong Kong,
Hong Kong Time is defined in the Interpretation and
General Clauses Ordinance (Cap 1), Laws of Hong Kong.
Section 67(2) of the Ordinance states that:
Hong Kong Time" (香港時間) means the time used for general
Hong Kong namely, 8 hours, or such other period as
may be determined by the Legislative Council by resolution under this
subsection or under section 16 of the Oil (Conservation and Control)
Ordinance (Cap 264), in advance of Universal Standard Time.
Hong Kong time is defined as UTC+8. The reference in
section 67(2) to the Oil (Conservation and Control) Ordinance is
actually a power given to the Legislative Council of
Hong Kong to
Hong Kong Time for the purposes of conserving oil, i.e. to
implement daylight saving time. However, no daylight saving time has
been observed since 1979.
Hong Kong Time was first set to
Local Mean Time
Local Mean Time (GMT+7:36:41) on 1
January 1885 at 13:00 by the then Royal Observatory Hong Kong. In
Greenwich Mean Time
Greenwich Mean Time was adopted as the basis for Hong Kong
Time, the time was set at 8 hours in advance of Greenwich Mean
Time. The current
Coordinated Universal Time
Coordinated Universal Time system was adopted as
an official time standard on 1 January 1972. However, the legal Hong
Kong Time still remained based on
Greenwich Mean Time
Greenwich Mean Time until it was
changed to Universal Standard Time in 1998 after the Hong Kong
The time ball in front of Marine Police Headquarters Compound, Tsim
Kowloon circa 1908.
The time ball tower at
Blackhead Point in 1908.
Hong Kong Time was determined by astronomical observations
Hong Kong Observatory using a 6-inch equatorial mount and a
3-inch Transit Circle. The time was announced to the general
public, particularly mariners, by dropping a 6-feet diameter time ball
from a mast exactly at 13:00 daily in front the Marine Police
Headquarters Compound, where it is visible from the Victoria Harbour.
In January 1908, the time ball was relocated to the hill of Blackhead
Point where it had even higher visibility. With the rise of radio
broadcast and the launching of Radio
Hong Kong in 1922, the importance
of the time ball decreased. It was decommissioned on 30 June 1933.
During the Second World War, the equatorial mount and transit circle
were lost. After the war, a pendulum clock was installed and regulated
by radio time signals from other timekeeping centres. Timing accuracy
gradually improved from the daily engineering tolerance of a few
seconds to one-fifth of a second.
In 1966, the pendulum clock in the Royal Observatory
Hong Kong was
replaced by a crystal oscillator timing system. In the same year, the
Royal Observatory started to broadcast the time directly with a 6-pip
time signal on 95 MHz. This continued until 16 September 1989.
In 1980, the Royal Observatory adopted a timing system based on a
Caesium beam atomic clock. This system narrowed the engineering
tolerance down to less than 1 millisecond. The frequency standard
of the clock is based on the primary standard used by Japan's
Communications Research Laboratory. In 1994, the atomic clock was
replaced with a newer model.
Hong Kong Time can be obtained from the Observatory's Network
Hong Kong adopted daylight saving measures in 1941. However, the
practice eventually declined in popularity and was eliminated after
ASEAN Common Time
^ Nautical Almanac Office (U S ) (17 May 2013). The Nautical Almanac
for the Year 2014. Government Printing Office. p. 262.
ISBN 978-0-16-091756-1. Archived from the original on 10 January
^ a b c d e f
Hong Kong Observatory, History of
Hong Kong Time
Service, archived from the original on 2010-11-27, retrieved
^ section 67 of the Interpretation and General Clauses Ordinance
Archived 2011-01-08 at the Wayback Machine., Laws of Hong Kong.
^ section 25 of the Adaptation of Laws (Interpretative Provisions)
Ordinance (26 of 1998) Archived 2008-07-29 at WebCite, Laws of Hong
Archived 2017-04-24 at the Wayback Machine.
Hong Kong Observatory
Hong Kong Time by
Hong Kong Observatory
Hong Kong Summer Time in history
Hong Kong Time service
Time in Asia
East Timor (Timor-Leste)
United Arab Emirates
British Indian Ocean Territory
Cocos (Keeling) Islan