27 JUNE

THE NEW ZEALAND GAZETTE

CLIMATOLOGICAL TABLE—Summary of the Records of Temperature, Rainfall, and Sunshine for May 1974—continued

The “normal” refers to the present site of the instruments. Standard periods for normals are: Temperature 1931–60, Rainfall 1941–70, 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 1974

General—May was a relatively mild month. Over the greater part of the country farmers reported good growth for the time of the year. However, in some northern districts of the North Island dry conditions persisted and the considerable rains of the 4th week were too late.

Rainfall—Rainfall was mainly close to normal. However, it was below normal by more than 25% on the West Coast with the Alps, the Canterbury high country and the greater part of Otago; in most eastern districts of the North Island; and in parts of Auckland and Northland. The week from the 23rd to the 29th was the wettest part of the month.

Sunshine—Sunshine was mainly close to normal. However, it was 20–30 hours below normal in Central and South Otago.

Temperatures—Temperatures were mainly up to 1½°C above normal, except in eastern districts north of Dunedin, where they were about normal. Snow was reported on the 7th to low levels in the South Island and also on the central high country of the North Island.

Weather Sequence—For the first two days of May an anticyclone was centred to the east while a depression over the Tasman Sea moved towards New Zealand. Rain was reported mainly in northern and north-eastern districts of the North Island, and also on the Southland coast. During the 3rd and 4th the depression developed two centres, one of which moved across the North Island to the east, while the other remained to the north of the country. A change to southerly winds brought rain in eastern districts. For the next two days an anticyclone over the North Tasman Sea covered most of the country and the weather was mainly fair. However, westerlies brought some rain to Fiordland. During the 7th and 8th a deep depression was passing far to the south and troughs of low pressure crossed the country, with some rain in most districts. Temperatures became colder and snow was reported to low levels in the South Island and also in the central high country of the North Island.

From the 9th to the 11th pressures were high to the north and low to the south. Freshening westerlies brought unsettled conditions to the Southland coast and Fiordland. Showers were also reported at times in Westland and also in some west coast areas north of Kawhia. During the next three days a trough of low pressure became stationary through Cook Strait with considerable rain in that area.

On the 15th and 16th an anticyclone centred to the east extended over the country, bringing mainly fair weather. For the next two days a weak trough of low pressure moved on to the South Island, bringing some rain once again to Southland and the West Coast. On the 19th the trough became slow-moving while pressures were low to the south-east. Showers were reported in some eastern districts, especially Gisborne and Hawke’s Bay. On the 20th and 21st an anticyclone centred to the east brought mainly fair weather. However, there was some rain in Northland, Gisborne and West-land.

The period from the 22nd to the 29th was by far the wettest part of the month. A depression remained almost stationary over the Western Tasman Sea, while another small depression with an associated trough of low pressure crossed the North Island and became stationary. From the 22nd to the 25th considerable rain was reported, especially in northern and western districts of the North Island and western and southern districts of the South Island. A brief temporary improvement occurred in many districts on the 26th as the trough retreated to the north, but showers still affected most northern districts. During the next two days the de-pression over the Western Tasman Sea moved slowly eastward, while the trough moved southward again. Rain became fairly general, except in the far south-west, with some considerable falls in northern districts. Temperatures were cold in the South Island. On the 29th the depression crossed the country near Cook Strait with considerable rain in that area.

On the last two days of the month a large anticyclone with centres to west and east covered most of the country, and the weather improved generally. However, rain was still reported at times, especially in the central high country of the North Island and the Gisborne ranges.

J. F. DE LISLE, Director.

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