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Time to talk Daylight Saving Time

Time to talk Daylight Saving Time

As summer comes to a close and autumn starts to set in, it is also nearing that time of year where we wind the clocks back by an hour. Daylight Saving Time will end in participating states (South Australia, New South Wales, Victoria, Australian Capital Territory , Tasmania) on the first Sunday in April (this year on April 3rd 2016). We will need to wind our clocks back one hour at 3am.

The modern idea of Daylight Saving Time was originally proposed by George Hudson in 1895. The Earth rotates around an axis that is 23.5° off vertical. This causes parts of the planet to be closer to the sun for half a year and further away for the other half. Hudson argued that as sunrise and sunset times vary throughout the course of the year due to the axial tilt of the Earth, the clocks should be wound forward and backward to deal with the variation.

It was several decades later, in 1916, when Austria and Germany became the first to use Hudson’s idea. Since then, Daylight Saving Time has been used in many countries across the world. It is particularly common in European countries where the days are shorter and prolonging sunlight supports industries and workplaces. Based on the amount of daylight, it allows more consistent starting times throughout the year. Daylight Saving Time reached peak popularity in the 1970s however many countries have since opted out.

daylight saving time

Daylight Saving Time in Australia

While moving the clocks forward by an hour in October each year ensures sunset can be as late as 9pm, Daylight Saving Time leads to a lot of time zone fragmentation across the country. In fact, the number of time zones is increased from three to five.

Between April and October, the continent is divided into three time zones.

  1. Australian Western Standard Time (AWST) – Western Australia uses
  2. Australian Central Standard Time (ACST) – the central states, South Australia, Northern Territory and also the New South Wales town ‘Broken Hill’
  3. Australian Eastern Standard Time (AEST) – Queensland, New South Wales, Victoria, Tasmania and Australian Capital Territory.

During October to March, keeping track of time in Australia becomes slightly more confusing. Queensland, Northern Territory and Western Australia stick to their original time zones. All the other states and territories transition to the Daylight Saving Time zone variants – Australian Eastern Daylight Time (AEDT) for New South Wales, Victoria, Tasmania and Australian Capital Territory and Australian Central Daylight Time (ACDT) for South Australia.

This interestingly means that the state of Queensland, which is further East than South Australia is half an hour behind the time in South Australia during the Daylight Saving Time period.

Daylight Saving Time allows for Australians to take advantage of summer weather and enjoy evenings after work outdoors. By spending time outside when the UV index is below 3 (typically after 5.30/6.00pm during summer months of the year), those in desk job/indoor occupations are able to replenish potential deficiencies in vitamin D from sunlight.

For more information on Daylight Saving Time in Australia, refer to the Safework SA website.

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Feature image: Wikipedia

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