May 1987:   It was warmer than usual over the whole country with rainfall below average in the North Island and above average in the South Island. Mean sealevel pressures were considerably above average, ranging from 8hPa above in the north and west to 5hPa above in the south and east of the country. Winds were lighter than usual in the north but with a strong westerly predominance. Speeds were high in the far south with the highest frequency of strong winds at Invercargill since 1973.

Rainfall: Northland had its lowest May rainfall for 10 years. Heavy rain on the 19th caused surface flooding and minor slips in Nelson. In South Canterbury and North Otago rainfall totals were more than twice normal for the month. Blocked culverts and stormwater in sewers caused problems in Timaru, with persistent rain from the 16th to 21st.

Some totals: North Egmont 784mm, Otira 641mm, Cropp Waterfall 1611mm, Milford 742mm, Rai Valley 402mm, Waimate 180mm, Palmerston 178mm; Cape Reinga 26mm, Waihi 47mm, Ongaonga 31mm.

Temperatures: Lower than usual minima resulted in below average mean temperatures from Coromandel north. Over the remainder of the country temperatures ranged up to 3C above normal. Inland South Island from North Canterbury to Southland had mean temperatures more than 1.5C above normal.

23.0C maximum at Napier on the 19th, -6.8C minimum at Molesworth on the 3rd.

Sunshine:  Eastern coastal stations from Bay of Plenty to Wairarapa and in Canterbury had more sunshine than usual. Elsewhere cloud conditions gave reduced sunshine as low as 2/3 normal in Manawatu and Westland. Paraparaumu and Levin had their lowest May sunshine totals since observations began in 1953 and 1955 respectively.

[Some totals: Kaitaia 132, Dargaville 120, Leigh 140, Tauranga 183, Whakatane 169, Rotorua 132, Mangere 132, Te Kauwhata 108, New Plymouth 108, Masterton 131, Dannevirke 117, Gisborne 159, Napier 168, Paraparaumu 93, Palmerston North 75, Levin 78, Wellington 112, Stratford 103, Manaia 101, Takaka 136, Westport 95, Hokitika 83, Greymouth 59, Nelson 156, Blenheim 159, Kaikoura 143, Mt Cook 81, Methven 147, Christchurch 161, Timaru 130, Palmerston 119, Dunedin Aero 103, Dunedin 95, Te Anau 100, Queenstown 94, Cromwell 115, Alexandra 106, Invercargill 84, Campbell Is 9, Chatham Is 64.]

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