1240

THE NEW ZEALAND GAZETTE

No. 60

CLIMATOLOGICAL TABLE-Summary of the Records of Temperature, Rainfall, and Sunshine for May 1973—continued

| Station | Height of Station Above M.S.L. | Means of A & B Max. Min. | Mean of A & B Normal | Difference From Normal | Air Temperatures in Degrees (Celsius) Absolute Maximum and Minimum | Maximum Fall Date | Rainfall in Millimetres Total Fall | No. of Rain Days | Difference From Normal | Maximum Fall Amount Date | Bright Sun-shine Hrs. |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Mount Bruce Reserve, April 1973 | 305 | 15.8 7.6 | 11.7 | ... | 19.4 12 | -1.5 25 | mm | 134 | 14 | ... | 28 22 | ...
| Waipukurau, April 1973 | 137 | 18.0 8.7 | 13.4 | +0.6 | 23.1 23 | 0.9 26 | 47 | 14 | -11 | 13 10 | 72
| Makahu Spur, March 1973 | 1,478 | 12.2 6.3 | 9.3 | ... | 18.4 2 | -0.7 27 | ... | ... | ... | ... ... | ...
| Makahu Spur, April 1973... | 1,478 | 9.0 3.6 | 6.3 | ... | 15.5 1 | -1.4 5 | ... | ... | ... | ... ... | ...
| Massey University, March 1973 | 61 | 21.1 12.5 | 16.8 | ... | 26.4 15 | 6.2 25 | 100 | 13 | ... | 65 12 | 164
| Murchison, April 1973... | 158 | 17.9 5.0 | 11.5 | ... | 23.2 4 | 0.0 3 | 119 | ... | ... | ... ... | ...
| Black Birch Range, 1,396 January 1973 | 1,396 | 15.5 6.9 | 11.2 | +1.3 | 23.0 22 | 0.4 12 | 50 | ... | -44 | 31 11 | ...
| Black Birch Range, 1,396 February 1973 | 1,396 | 16.4 8.7 | 12.6 | +2.8 | 31.3 7 | 0.1 13 | 10 | 7 | -92 | 4 21 | ...
| Black Birch Range, 1,396 March 1973 | 1,396 | 12.3 5.8 | 9.1 | +0.4 | ... | ... | ... | ... | ... | ... ... | ...
| Mount John, January 1973 | 1,027 | 20.5 8.5 | 14.5 | +0.9 | 29.5 21 | ... | 14 | 3 | -32 | 12 10 | 309
| Rarotonga Airport, March 1973 | 7 | 30.2 23.8 | 27.0 | +1.4 | 31.9 19 | 21.2 25 | 319 | 20 | +68 | 76 16 | 164
| Mohakatino Station, Mokau, April 1973 | 46 | 17.6 11.5 | 14.6 | ... | 21.1 19 | 4.1 21 | 98 | 15 | -37 | 30 10 | ...

The “normal” refers to the present site of the instruments. Standard periods for normals are: Temperature 1931–60, Rainfall 1921–50, Sunshine 1935–60. No normals are available for stations with only short records.

*Indicates that the sunshine recorder is not located at the station but is in the near vicinity.

A rain day is a day with rainfall equal to or greater than 0.1 mm.

Where the extremes of temperature and rainfall have occurred more than once during the month, the date of the first occurrence is given.

NOTES ON THE WEATHER FOR MAY 1973

General—May was a mild, windy month with an unusually high frequency of winds from between west and south-west. This caused cloudy, wet weather in Southland and on the West Coast but sunny, dry weather in areas such as Gisborne and Northland. The mild weather was appreciated by the farmers, who found conditions generally favourable, with quite good growth for the time of the year. However, in Marlborough and North Canterbury the persistence of a below-average rainfall for the seventh successive month caused a serious shortage of feed.

A small local tornado caused some damage at Weymouth, on Manukau Harbour, on the 9th.

Rainfall—Rainfall was above normal in nearly all western districts south of Auckland, also in Southland with most of Otago and in Wairarapa. The surplus exceeded 50 percent in North Taranaki, Manawatu, Buller, and north Westland, Fiordland, and most of Southland. Elsewhere rainfall was below normal, with a deficiency of more than 50 percent in eastern Northland, Gisborne, and northern Hawke’s Bay, and a considerable part of Nelson and Marlborough.

Temperatures—Temperatures were mainly above normal by 1°C. Departures were somewhat greater over the North Island than over the South Island.

A cold spell on the 21st brought snow to low levels in parts of the South Island.

Sunshine—Sunshine was below normal by 20–50 hours over the greater part of the South Island and also in Manawatu, with greatest deficiencies on the West Coast, where Greymouth received only 58 hours. Northern and most eastern districts of the North Island were favoured with 20–35 hours above normal.

Weather Sequence—On the first 2 days of May pressures were high over the country and to the south, but a weak south-westerly trough brought scattered showers, especially in Taihape, Manawatu, and Westland. Pressures remained high to the north on the 3rd and 4th, but a depression was moving eastward from Tasmania and its warm front brought rain to western districts from Waikato southward. The depression next moved to the east of the South Island and on the 5th and 6th conditions remained somewhat similar, except that rain also spread to some eastern districts.

On the 7th a very deep depression near Macquarie Island moved eastward and during the next 2 days there was considerable rain west of the ranges and also on the Southland coast, while gales buffeted Cook Strait. Westerly conditions persisted on the 10th as another depression over the south Tasman Sea passed close to Southland, causing rain there and in Fiordland.

The next 4 days were particularly unsettled. During the 11th and 12th a secondary depression formed and moved north-eastward, over New Zealand with an associated trough, while pressures rose rapidly over Campbell Island. Rain was general except in parts of Hawke’s Bay and Gisborne, and gales buffeted Canterbury and Cook Strait. During the next 2 days a depression over the north Tasman Sea crossed Northland while pressures were high to the south and east of the South Island. The weather cleared over the South Island but further considerable rain was reported in the North Island. From the 15th to the 17th this depression was off East Cape while further troughs crossed the country associated with depressions far to the south. Rain was reported over the whole of the South Island and most of the North Island.

During the 18th and 19th a very deep depression passed to the south and the associated trough of low pressure brought rain mainly to western districts of both Islands and Southland. On the 20th and 21st a cold south-westerly change brought fairly general rain, with snow to low levels in parts of the South Island. For the next 2 days conditions were once more of the westerly type, with depressions passing far to the south, causing rain on the West Coast. Another south-westerly change on the 24th extended the rain to Southland and some western areas of the North Island.

A ridge of high pressure extending from an anticyclone to the north brought settled conditions on the 25th. However, there was a return to westerly conditions once more on the following 4 days, with rain affecting western districts of both Islands and the Southland coast. One of the troughs of low pressure associated with these westerly conditions became slow-moving near Auckland on the 30th with rain still affecting some western districts. On the last day of the month an anticyclone was centred near Northland but westerlies once again brought some rain to Fiordland.

J. F. GABITES, Director.

(N.Z. Met. S. Pub. 107)