December was a record-setting wet month, with not just Nelson and Golden Bay setting rainfall extremes, but also in the Bay of Plenty, Waikato and Wanganui.
A heavy deluge, which sparked a state of emergency in the Nelson and Tasman districts, was part of a December that saw more than double normal rainfall for most of the North Island and northern South Island but less than half normal rainfall in Southland and Otago, according to NIWA's national climate summary for the month, released on Thursday.
NIWA's principal climate scientist Andrew Tait said that was because the country experienced more northeasterly winds than normal.
Nelson received more than six times and Takaka received more than eight times their normal December rainfall, which were the highest December totals there since records began in 1941 and 1976 respectively.
In Takaka, the main centre in Golden Bay, on December 14, 392 millimetres of rain fell, the highest ever one-day rainfall there, beating the previous record of 259mm in 1990.
Highest December rainfall totals were also recorded in Kerikeri, Te Puke, Rotorua, Hamilton, Stratford, Hawera, Wanganui and Motueka.
Conversely, in the south and west of the country, rainfall was well below normal. Lowest December rainfall totals were recorded in Milford Sound, Puysegur Point, Dunedin, Manapouri, Queenstown, Lumsden, Gore, Invercargill, Balclutha and Tiwai Point.