NZ weather summary May 1956

[Rwood]

May 1956:  A spell of warm sunny weather which had carried over from the end of April ended on 4 May. Cloudy, unsettled weather then predominated for the rest of the month with frequent heavy rain, especially in the North Island. Pasture growth was good for the time of year, but in parts of Northland and Hawkes Bay the ground was much too wet. On the 18th and for several days afterward, exceptionally heavy seas caused damage to east coast beaches between Hawkes Bay and the Coromandel peninsula. A small local tornado occurred at Te Awamutu on the 14th.

Rainfall: Rainfall was more than double normal in northeastern Northland, in the Rotorua-Waikaremoana-Wairoa area, and also in South Canterbury and Otago. Over most other districts conditions were about average or somewhat wetter, but in Westland, North Canterbury and the greater part of Southland rainfall was appreciably below normal.

An exceptional downpour occurred in a thunderstorm in and north of Whangarei on the 26th, with flooding which caused serious damage to property, especially in the town itself. At Glenbervie forest near the city, 2.96” were recorded in an hour. There were many other heavy falls of rain during the month. Parts of Northland suffered from flooding on the 5th, 9th and 14th. Nelson Aerodrome was under water on the 21st. Heavy falls on the 28th-29th led to flooding in Te Puke and in Takaka. The Glenbervie total of 21.14” set a new monthly record there, surpassing April’s 19.74”.

Temperatures: Temperatures were warmer than usual in the North Island and in western and northern districts of the South Island, mainly by 2F-4F. Elsewhere they were slightly below normal. There were 2 spells of wintry southeasterly weather, from the 7th to the 10th and the 14th to the 19th. During the latter snow fell below 2000 feet in the south.

Sunshine: It was cloudier than usual except in the west and south of the South Island [and Manawatu-Horowhenua]. The deficiency exceeded 50 hours in Marlborough, Wairarapa, Hawkes Bay, Gisborne, Bay of Plenty and parts of Northland. Eastern districts from Wairarapa to Gisborne have not previously received so little sunshine in any month.

[Some totals: Te Hapua 97, Kaitaia 114, Kerikeri 87, Whangarei 76, Auckland 107, Tauranga 107, Taupo 103, Hamilton 120, Whatawhata 99, New Plymouth 135, Masterton 59, Gisborne 59(still a record low for any month), Napier 71, Paraparaumu 122, Ohakea 116, Foxton 137, Palmerston Nth 112, Levin 133, Wellington 97, Wanganui 121, Westport 156, Hokitika 164, Greymouth 163, Haast 166 (102 more than in April!), Nelson 146, Blenheim 117, Grassmere 111, Mt Cook 81, Methven 118, Christchurch 101, Tekapo 102, Timaru 93, Waimate 107, Omarama 113, Dunedin Aero 114, Dunedin 104, Queenstown 98, Alexandra 118, Invercargill 123, Raoul Is 99].

Sources: NZ Met. Misc. pub. 107 (Climatological table, NZ Gazette) and NZ Met. Misc. pub. 109 (Meteorological Observations) - additional comments by the poster.

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[Rwood]

Musselburgh, Dunedin had 8.60” (219mm), still its record high for May. I recall a family trip there, leaving sunshine in the south and arriving to mist and a fine but very soaking drizzling easterly rain that persisted for a long while. Invercargill had a fairly benign month, with rainfall well down and sunshine well up on average - not by any means a pointer to its Mays in the coming decades however.

[ato2]

What a miserable month for sunshine, for so many places!

[Rwood]

Yes, the north/east 3/4 of the NI was particularly bad. Normal or not far below from New Plymouth to Kapiti. The April-June period delivered a lot of rain to much of the NI. The Haast "reversal" April-May (64 hrs followed by 166) is one of the more bizarre records in NZ's sunshine history ...

The next history post will be for a much brighter May ...   

[Rwood]

Note re sunshine "departures from normal" reporting prior to about 1961: These were based on averages calculated for all years up to 1950. There were 2 main reasons these averages were generally too high: (1) observations prior to 1935 were not generally centrally verified, and equipment not standardised - some of the older ones, especially before 1925-1930, were unrealistic and too optimistic; (2) the period 1930-1950, especially 1935-1950, was for much of the country sunnier than long term records show. As a consequence, reports of the post-1950 years give exaggerated impressions of deficits and understated impressions of surpluses. The above comments apply mostly to the North Island, but not exclusively. The greatest anomaly in the old averages was at Napier, whose old readings prior to about 1925 were far too high - its amended average for 1935-1960 was 125 hours less than the period average to 1950.