CLIMATOLOGICAL TABLE—Summary of the Records of Temperature, Rainfall, and Sunshine for April 1966—continued

LATE RETURNS

The “normal” refers to the present site of the instruments. The standard periods for normals are: for temperature 1931–60, for rainfall 1921–50, and for sunshine 1935–60. No normals are available for stations with only short records.

Sunshine recorded is not located at the station but is in the near vicinity.

NOTES ON THE WEATHER FOR APRIL 1966

General: Although April was a sunny month, it was also wetter than usual in most districts. As in March, the middle part of the month was comparatively settled and sunny. Farmers reported very favourable conditions, with good growth for autumn.

Two small local tornadoes were reported, in Waitara on the 9th and in Levin on the 24th.

Rainfall: Rainfall was above average over the greater part of the country. It was more than double the average value about Cook Strait. The main areas which were appreciably drier than usual were South Canterbury and Otago, where a considerable area near the coast had less than half the average rainfall; Hawke’s Bay, Gisborne, Auckland, and the east coast of Northland, all with about two-thirds of the average value.

In Wellington and the Marlborough Sounds the 25th was by far the wettest day, with totals of 3–8 in. and flooding in the Hutt Valley on the 26th. Most of the rain fell during the night.

Temperatures: Temperatures were mainly close to average. However, inland districts of the southern half of the South Island were a degree warmer than normal.

Sunshine: Sunshine was mainly 10–30 hours above average. Northland, Gisborne, Hawke’s Bay, and parts of Waikato and North Taranaki were favoured with even higher surpluses. However, on the West Coast and the Southland coast and in the Southern Lakes district sunshine was only average.

Weather Sequence: At the beginning of the month pressures were low to the east of the North Island and high over the western Tasman Sea, with south-westerly winds predominating over New Zealand. Rain or showers were reported on western coasts of both islands and in Southland. On the 2nd, with pressures still falling to the east, winds turned to southerlies, bringing a period of showers to Canterbury, the Kaikoura coast, Wellington, and Wairarapa. Some heavy downpours occurred in Canterbury, with hail. Showers persisted in a few areas on the following day; but on the 4th, as a small depression passed close to Southland, rain was again recorded, mainly in western districts and Southland. This rain cleared on the 5th with rising pressures over the South Island. However, a small depression which crossed the North Island caused some light rain there, in Nelson, and on the Kaikoura coast.

On the 6th a deep depression passed far to the south and the associated trough of low pressure brought rain to the Southland coast and the West Coast. On the following day an anticyclone passed over the North Island and the weather was mainly fair.

During the 8th and 9th a depression from the mid-Tasman area passed close to Southland. The associated trough of low pressure brought considerable rain to the West Coast and parts of Taranaki and some rain to many other areas. However, eastern districts from Otago to southern Hawke’s Bay were not affected. A downpour was reported in Hawera with flooding.

During the 10th and 11th an anticyclone advanced slowly over the Tasman Sea and south-westerlies brought showers to the Southland coast and the West Coast. This anticyclone crossed the country from the 12th to the 15th with mainly fine weather. However, a depression passed to the north, and in the easterlies showers were reported on parts of the east coast of Northland and in the Gisborne district. During the 16th and 17th a trough associated with a deep depression to the south brought rain to the South Island, Wellington, and Wairarapa. For the next two days an anticyclone was centred over the Tasman Sea, and south-westerlies brought rain once again to the Southland coast and the West Coast, with a few showers also in Waitomo, Waikato, and Auckland. By the 20th the anticyclone covered New Zealand, with fine weather.

During the 21st and 22nd the weather deteriorated once more in Fiordland and on the Southland coast as a trough of low pressure became stationary in that area with the formation of a small depression. As the trough moved over the South Island during the next two days the weather cleared temporarily in Southland but rain spread over the remainder of the West Coast and to Nelson and Wellington. A depression from the north Tasman Sea then crossed the North Island while the trough was stationary through Cook Strait. For the greater part of the country the 25th and 26th were the wettest days of the month, with some particularly heavy falls about Cook Strait and flooding in the Hutt Valley. The only areas which escaped this rain were Fiordland and Otago.

An anticyclone brought fine weather during the next two days, apart from showers in Coromandel and Gisborne, and on the Southland coast. On the 29th a depression from the north Tasman moved past Southland. In the warm northerlies rain was general except in some eastern districts. Considerable falls were reported in the Alps and in the Waitomo-Taupo-Bay of Plenty area. On the last day of the month warm northerlies still prevailed, with rain on the West Coast, in Nelson, and on the Southland coast.

J. F. GABITES, Director.

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