In the earliest days of European settlement in New Zealand each of the fledgling settlements effectively kept its own time - with up to 50 minutes variation between one part of the colony and another. Each locality kept time 12 hours in advance of Greenwich mean time (GMT) but because local time calculations were based on the meridian (noon, or when the sun is highest in the sky) and New Zealand spreads over 12 degrees of longitude there was inevitably variation.
On 2 November 1868, New Zealand officially adopted a standard time to be observed nationally, and was perhaps the first country to do so. It was based on the approximate mean longitude of the islands of New Zealand, 172°30´ East of Greenwich, that is, 11 hours 30 minutes in advance of Greenwich mean time. This standard was known as New Zealand mean time, and was observed until 1927 when the clocks were advanced one hour for the summer period (New Zealand summer time) from the 1st Sunday in November to the 1st Sunday in March: The Summer Time Act 1927. This daylight-saving measure was not well received, and in the following year the advance was reduced to half an hour from the 2nd Sunday in October to the 3rd Sunday in March.
By The Summer Time Amendment Act 1933, the period of summer time was extended from the last Sunday in September to the last Sunday in April, commencing in 1934.
During the Second World War the clocks in New Zealand were not put back for the winter and the 1/2 hour advance was continued for the duration of the War. Since this was equivalent to adopting a new standard time meridian, the position was made permanent, effective from 1 January 1946, by the Standard Time Act 1945, in effect changing what was formerly known as New Zealand summer time to New Zealand standard time. New Zealand standard time is defined in the Act as the time corresponding to the longitude of 180° east of Greenwich, being 12 hours in advance of Greenwich mean time. This continued unchanged until 1974.
The Time Act 1974 empowered the Governor-General to declare a period during which daylight time is to be observed by Order in Council, fixed as a one hour advance on New Zealand standard time and known as New Zealand daylight time. This corresponds to a longitude of 195° East of Greenwich, 13 hours in advance of Greenwich mean time.
The public response to a trial period of daylight time, from the first Sunday in November 1974 to the last Sunday in February 1975, was generally favourable. Subsequently the New Zealand Time Order 1975 fixed the period of observance from the last Sunday in October each year to the 1st Sunday in March of the year following.
As a consequence of a survey conducted in 1985, after 10 years experience with daylight time, a trial period of extended daylight time was held in 1989/90 from the 2nd Sunday in October to the 3rd Sunday in March. Again the public response was generally favourable and a new Daylight Time Order 1990 declared that daylight time would commence at 2.00am New Zealand standard time on the 1st Sunday of October in each year and ceasing at 2.00am New Zealand standard time on the 3rd Sunday in March in the following year.
On 30th April 2007, the Minister of Internal Affairs announced a further extension to daylight saving by three weeks, for a total of 27 weeks. This to take effect from the last Sunday in September 2007 and ending on the 1st Sunday in April the following year.
The Chatham Islands
Main town Waitangi, Longitude 176W33 Latitude 43S57
First mention of the Chatham Islands (850 km east of Christchurch) was made in the Standard Time Amendment Act 1956 which states that "The time for general purposes in the Chatham Islands shall be forty-five minutes in advance of NZ standard time". This Act is effective from 1 January 1957. The Time Act 1974 defines daylight time in the Chatham Islands as being 1 hour 45 minutes in advance of New Zealand standard time.
This was researched by Carol Squires.
References: NZ Dept of Internal Affairs, NZ High Court Auckland Library, Auckland Public Library, New Zealand Herald, and Astrological Society of NZ Inc Journal of the Seasons, Vol 2, 1975.