31 JANUARY

THE NEW ZEALAND GAZETTE

CLIMATOLOGICAL TABLE—Summary of the Records of Temperature,Rainfall,'and Sunshine for December 1973—continued

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 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 DECEMBER 1973

General—Pressures were unusually high to the south-east of the South Island in December, and easterly winds were somewhat more frequent than usual. It was a dry month, and also warm and sunny except in the east. The weather was particularly favourable for haymaking but many farmers, especially in Northland, found conditions too dry.

Rainfall—Rainfall was below normal over almost all the country, mainly by about 40 percent. It was less than half the normal value over almost the whole of Northland; in the greater part of Taranaki, Wanganui and Manawatu; and also in the greater part of Otago and Southland.

The only two periods of considerable and fairly general rain were the 17th and 18th and the 24th and 25th. Many stations received very little or no rain in the first half of the month.

In a thunderstorm at Taupo in the late afternoon of Christmas Day 30 mm were recorded in half an hour, an unusually heavy downpour.

Temperatures—Temperatures were mainly above normal by about 1°C. However, in some coastal areas, mainly in the east, they were only normal.

This was the 4th successive month of generally warm temperatures, and the year 1973 has been a warm one.

Sunshine—Sunshine was mainly above normal by 30–80 hours. However, on the east coast from Marlborough to Bay of Plenty it was only normal.

New Plymouth’s total of 293 hours was one of the highest ever recorded there for December; and Paraparaumu’s total of 300 hours was also unusually high.

Weather Sequence—For the first two days of December a depression near the Chatham Islands was moving away and a rather cold south-westerly airstream covered the country, with scattered light showers. On the following day an anticyclone was centred over the North Island and the weather was fine. During the 4th and 5th a deep depression near Macquarie Island moved eastward and the associated trough of low pressure crossed the South Island but soon became weak. In the warmer north-westerlies rain was reported on the West Coast with a few isolated showers elsewhere.

Pressures were particularly high over the country during the period from the 6th to the 16th, with fine dry weather predominating except in some eastern districts. At first an anticyclone was centred to the south-east of the South Island. On the 7th another high pressure centre developed west of the North Island and some rain was reported in Fiordland. For the next two days a belt of high pressure covered the South Tasman Sea and the South Island, but pressures were low to the north-east. A weak trough brought light showers to some eastern districts from Timaru northward and temperatures became cooler. Conditions remained somewhat similar on the 10th, when light showers affected mostly areas from Invercargill to Christchurch. Conditions remained very similar for another four days with the belt of high pressure almost stationary, but the depression to the north-east slowly moving away. During this period showers affected mainly areas from Gisborne to eastern Northland. By the 15th and 16th the main centre of high pressure lay to the east of the North Island, and the weather cleared in most eastern districts. However, some showers were reported at times in the North Island ranges.

During the 17th and 18th a trough of low pressure with a small depression on it crossed the country from south-west to north-east. Considerable and welcome rain was reported as far north as