Australia uses three main time zones: Australian Western Standard Time (AWST; UTC+08:00), Australian Central Standard Time (ACST; UTC+09:30), and Australian Eastern Standard Time (AEST; UTC+10:00). Time is regulated by the individual state governments, some of which observe daylight saving time (DST). Australia's external territories observe different time zones. Standard time was introduced in the 1890s when all of the Australian colonies adopted it.
Before the switch to standard time zones, each local city or town was free to determine its local time, called local mean time. Now, Western Australia uses Western Standard Time; South Australia and the Northern Territory use Central Standard Time; while New South Wales, Queensland, Tasmania, Victoria, and the Australian Capital Territory (ACT) use Eastern Standard Time. Daylight saving time is used in South Australia, New South Wales, Victoria, Tasmania, and the ACT. It is not currently used in Western Australia, Queensland or the Northern Territory.