January 1975: Like many previous months, January was marked by an unusually high frequency of north-easterly winds, bringing excessive cloud to some eastern districts. In the west it was one of the warmest months on record. In most areas conditions were rather dry in the first half of the month, but good rains in the second half freshened up pastures.
Rainfall: Rainfall was above normal in the North Island except for eastern and northern Northland and Manawatu. It was also above normal in most of Nelson, Marlborough, and Canterbury. It was more than double the average in many areas east of the main ranges north of Timaru and about parts of the Coromandel and Kaimai ranges. It was less than half the normal value in parts of Southland and South Otago and on the West Coast. On the night of 28-29 January an exceptional fall of rain, amounting in places to nearly 200mm, of which more than 100mm fell in 6 hours, was reported in parts of the upper plains of South Canterbury, causing serious flooding, especially at Peel Forest, where four lives were lost. At Rangiora on the 16th, 35mm of rain were recorded in half an hour, an exceptionally intense fall for this part of the country. As in December, thunderstorms were unusually frequent, especially over the North Island from the 6th to the 17th.
Some monthly totals (mm): Kawerau 241, Hamilton 189, Waikaremoana 395, Napier 102, Wairoa 365, Nelson 146, Darfield 187, Fairlie 181; Cape Reinga 3, Foxton 40, Hokitika 71, Milford 260, Wanaka 25, Dunedin 33, Invercargill 37.
Temperatures: Temperatures were above normal, mainly by 2C. Departures were highest in the west, and New Plymouth had its warmest January in over 30 years of observation. The first half of the month was considerably warmer than the second half, with persistently high maxima in some western districts. New Plymouth’s maximum of 30.4C on the 4th was its highest ever; and Wellington’s maximum of 30.1C on the 5th was its highest for January.
35.8C maximum at Ashburton on the 5th, 1.1C minimum at Mt John on the 2nd.
Sunshine: East of the main ranges sunshine was below normal, mainly by 30-70 hours, with some particularly low values in Canterbury and Central Otago. In western districts sunshine was mainly above normal by 30-40 hours, but in Northland it was above by up to 90 hours.
[Some totals: Kaitaia 306, Dargaville 305, Leigh 291, Auckland 264, Tauranga 266, Whakatane 267, Taupo 238, Auckland Aero 278, Hamilton 243, Taumarunui 229, New Plymouth 277, Masterton 196, Dannevirke 180, Gisborne 214, Napier 227, Wairoa 214, Paraparaumu 267, Ohakea 274, Palmerston North 236, Levin 238, Wellington 242, Stratford 238, Wanganui 261, Westport 253, Hokitika 249, Greymouth 264, Haast 224, Riwaka 273, Nelson 259, Blenheim 238, Kaikoura 194, Mt Cook 134, Mt John 170, Methven 166, Christchurch 166, Timaru 145, Waimate 110, Omarama 170, Palmerston 129, Dunedin 152, Oamaru 141, Te Anau 153, Queenstown 166, Alexandra 168, Gore 189, Invercargill 164].
Sources: NZ Met. Misc. pub. 107 (Climatological table, NZ Gazette) and NZ Met. Misc. pub. 109 (Meteorological Observations) - additional comments in italics.