Victoria moved to Australian Eastern Daylight Time this morning at 2 am.

The legal mechanism for this process is found in the Summer Time Act 1972.

Under s 3 of the Act, the Governor-in-Council proclaims the start and finish of summer time. Currently, this is found in Government Gazette G35, 30 Aug 2007, p 10. The relevant part provides:

1. Subject to paragraph 2, the period of summer time shall commence at the hour of two o’clock in the morning standard time on the first Sunday in October in each year and end at the hour of two o’clock standard time (three o’clock summer time) in the morning on the first Sunday in April the following year.

2. In the year 2007 the period of summer time shall commence at the hour of two o’clock in the morning standard time on the last Sunday in October, being Sunday 28 October 2007.

Although this probably seems a bit twee, it can be significant in some summary criminal matters, especially those involving the use of breathalysers for drink-drive charges. Those instruments must be manually adjusted to account for daylight saving time. If the police forget to do this, it can affect the statutory three-hour period for demanding breath tests under Road Safety Act 1986 s 49. And in cases that occur on the cusp of a new day, it might also affect the correct date of the offence.