NZ weather summary December 1971

[Rwood]

December 1971: December was a warm month, and dry in the South Island. It was a good month for stock, though parts of Marlborough and Canterbury were too dry. As in most previous months of 1971, there was an unusually high frequency of northeasterly winds.

Rainfall: In the South Island rainfall was below normal, except in western Southland. In Marlborough, Canterbury and parts of Central Otago it was from a tenth to a half of the normal value. In the North Island rainfall was mainly within 50% of the normal value. However, in parts of Auckland, Waikato, Bay of Plenty and northern Hawkes Bay it was more than 50% above; while in Wellington it was more than 50% below normal. Very little rain was recorded anywhere in the country from the 10th-18th, and most places had none during this period.

600mm rainfall at Milford, 7mm at Grassmere, 9mm at Tekapo.

Temperatures:  Temperatures were above normal, mainly by 1.0-1.5C.

31.8C maximum at Darfield on the 25th.

Sunshine: Over most of the North Island and in Nelson, Marlborough, coastal South Canterbury, Otago and Southland sunshine was 20-80 hours below normal, with highest deficiencies in Bay of Plenty and Taupo. Elsewhere it was mainly close to average or a little above.

[Some totals:  Kaitaia 167, Kerikeri 152, Whangarei 136, Leigh 174, Auckland 205, Tauranga 175, Whakatane 172, Taupo 156, Opotiki 149, Auckland Aero 223, Hamilton 176, New Plymouth 218, Masterton 205, Gisborne 220, Napier 209, Wairoa 205, Paraparaumu 239, Ohakea 213, Kairanga 205, Palmerston North 193, Levin 200, Wellington 238, Stratford 204, Ohakune 160, Wanganui 194, Takaka 168, Westport 187, Hokitika 197, Greymouth 180, Haast 183, Riwaka 199, Nelson 191, Blenheim 208, Grassmere 176, Kaikoura 182, Mt Cook 169, Mt John 229, Methven 199, Christchurch 200, Tekapo 240, Timaru 139, Waimate 138, Omarama 197, Palmerston 161, Dunedin Aero 145, Dunedin 143, Oamaru 148, Queenstown 211, Alexandra 192, Invercargill 157, Raoul Is 185, Campbell Is 99, Chatham Is 212 {2nd highest}].


Sources: NZ Met. Misc. pub. 107 (Climatological table, NZ Gazette) and NZ Met. Misc. pub. 109 (Meteorological Observations).

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[Rwood]

Another warm month with northeasterlies more common than usual. The 2nd month in a row with Wellington near the top of the sunshine readings (not quite as uncommon as some might suppose).

With the unusually high frequency of northeasterly airflows, the annual sunshine totals had some unusual characteristics. All of the normally sunniest regions of the country, apart from the Mackenzie which was in surplus, had substantial deficits. Hokitika and Haast both outscored Napier and Gisborne; Wellington headed Takaka by 20 hours (but see below!), and was only 3 hours behind Whakatane.

Highest totals: Mt John 2424, Tekapo 2312, Riwaka 2264, Blenheim 2244, Nelson 2238, Ohakea 2185, Paraparaumu 2173, New Plymouth Aero 2148, Omarama 2146, Auckland Aero 2134.

In 1972 the anomaly was completely reversed with a high frequency of southwesterlies; 1972 & 1973 were very sunny years at Takaka and it headed Wellington by 447 hours and 530 hours respectively (even though Wellington was average in 1972 and not far below in 1973).

[tich]

1971 a La Nina year?

[Rwood]

Yes - nearly every month from September 1970 to November 1971 met the SOI La Nina threshold. The related ONI index was in La Nina territory from June 1970 to January 1972.