August 1975:  August was a mild month, and in the South Island it was unusually cloudy and wet. Exceptionally strong north-westerly winds which had commenced in Southland and parts of Otago on 31 July, spread into other eastern districts as far north was Wairarapa on 1 August. Observations at Timaru Aerodrome, Christchurch Airport, Kaikoura Peninsula and the northern end of Lake Wairarapa all indicated winds of at least hurricane force, i.e. averaging at least 64 knots over a period of 10 minutes. Widespread damage was reported, including devastation of large areas of forest, houses deroofed, buildings demolished, and 7 power pylons blown down near the upper Selwyn River in Canterbury. Unusually high gusts included 105 knots on Kaikoura Peninsula, 93 knots at Christchurch Airport, and 92 knots at Eyrewell Forest, north-west of Christchurch. Small local tornadoes caused some damage at Governors Bay on the 1st and at Kaitaia on the 13th.

Rainfall: Rainfall was above normal over nearly all the South Island and also over most of the North Island west of the ranges and south of Hamilton and Tauranga. It was more than double the average over most of Canterbury and parts of Otago, Nelson, and Manawatu. 2-day rainfalls of 130-200mm on the 19th and 20th around Lyttelton and banks Peninsula caused considerable flooding, especially of the Heathcote River in Christchurch.

Some monthly totals (mm): Rotorua 215, Pahiatua 234, Palmerston North 160, Kelburn 246, Stratford Mountain House 882, Hokitika 367, Nelson 193, Ashburton 174, Timaru 130; Gisborne 42, Napier Aero 35, Wairoa 26, Alexandra 16.

Temperatures:  Mean temperatures were mainly above normal by up to 1C. Snow fell to low levels in parts of the South Island on the 1st and 28th, and on the high country of both islands on the 7th and 8th.
 
23.5C maximum at Kaikoura on the 1st, -7.2C minimum at Twizel on the 8th.

Sunshine:   Sunshine was below normal by 40-70 hours except east of the ranges in the North Island, where it was mainly close to normal. Dunedin’s 68 hours, Queenstown’s 71 hours, and Greymouth’s 63(**) hours were all record low totals for August. {(**) also the NZ record low for August.}

[Some totals: Kaitaia 133, Dargaville 125, Whangarei 129, Auckland 128, Tauranga 134, Whakatane 163, Taupo 113,  Hamilton 119, Te Kuiti 97, Taumarunui 85, New Plymouth 113, Masterton 118, Dannevirke 115, Gisborne 163, Napier 148, Wairoa 168, Paraparaumu 101, Ohakea 121, Palmerston North 96, Levin 91, Wellington 104, Stratford 89, Wanganui 106, Westport 87, Hokitika 76, Greymouth 63, Haast 95, Riwaka 134, Nelson 127, Blenheim 152, Grassmere 136, Kaikoura 125, Mt Cook 83, Mt John 133, Methven 117, Christchurch 113, Timaru 98, Waimate 89, Omarama 117, Palmerston 85, Dunedin 68, Te Anau 74, Queenstown 71, Alexandra 103, Gore 96, Invercargill 84, Chatham Is 65 (lowest)].

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