AEDT meaning in Regional ?

Answer:

What is Australian Eastern Daylight Time mean?

Each state and territory of Australia determines whether or not to use daylight saving time (DST). However, during World War I and World War II all states and territories had daylight saving by federal law, under the defence power in section 51 of the constitution. In 1968, Tasmania was the first state since the war to adopt daylight saving. In 1971, New South Wales, Victoria, Queensland, South Australia, and the Australian Capital Territory also adopted daylight saving, while Western Australia and the Northern Territory did not. Queensland abandoned daylight saving in 1972. Queensland and Western Australia have observed daylight saving over the past 40 years from time to time on a trial basis.

New South Wales, the Australian Capital Territory, Victoria, Tasmania and South Australia observe DST every year. This has resulted in three time zones becoming five during the daylight-saving period. South Australia time becomes UTC+10:30, called Central Daylight Time (CDT), possibly with "Australia" prefixed (ACDT). The time in the southeastern states becomes UTC+11:00, using "Eastern" in the time zone name, Eastern Daylight Time (EDT), respectively Australia Eastern Daylight Time (AEDT).

Officially, the change to and from DST takes place at 02:00 local standard time (which is 03:00 DST) on the appropriate Sunday.

Of the states that observe DST, most began on the last Sunday in October, and ended on the last Sunday in March, until 2007. Tasmania, owing to its further southern latitude began DST earlier, on the first Sunday in October, and ended on the last Sunday in March.

In the 2007-08 season, Tasmania started on the first Sunday in October whilst the ACT, NSW, Vic and SA started in the last Sunday in October. As part of the transition to earlier daylight saving, those states and Tasmania all finished on the first Sunday in April. For subsequent years, DST in the south-eastern states and SA now starts on the first Sunday in October, finishing on the first Sunday in April the next year.

Western Australia was not affected by these changes to DST, being the only state in 2007-08 to observe daylight saving from the last Sunday in October to the last Sunday in March. However, since 2009, it is on Standard time all year round.

Queensland (AEST UTC+10:00), Northern Territory (ACST UTC+09:30) and Western Australia (AWST UTC+08:00) do not observe DST.

reference

Full Form	Category
Academy for Engineering and Design Technology	Academic & Science
Aviation Environmental Design Tool	Governmental
Articulated Electric Drive Trailer	Governmental
Am Ende Des Tages	International
Australian Eastern Daylight Time	Regional