Climate scientists say last year will be remembered for the number of extreme events, including one storm so severe it was dubbed a "weather bomb".
The National Institute of Water and Atmospheric Research (Niwa) said records were set in many months for rainfall and temperature.
Senior climate scientistJim Salinger said May to December was influenced by the return of El Nino, which gave windier conditions, including persistent westerly and southwesterly winds .
Dr Salinger said the upper North Island experienced many of the country's 12 flooding and high rainfall events, including 22 days of thunderstorms.
The "weather bomb" of June 18-20 caused flooding and slips, with rainfall totalling 160mm to 210mm throughout Northland, the northern part of Auckland and Coromandel.
A peak gust of wind of 124 km/h was recorded at Musick Pt in eastern Manukau City.
A state of emergency was declared in flooded Putaruru and more than 20,000 Waikato homes lost power.
Big hailstones struck Massey, in Waitakere City, on July 3 during a fall that lasted 30 minutes.
Tornado-like winds ripped roofing iron off a house and toppled fences in Blockhouse Bay, Auckland, on October 25 and another tornado was seen in the city on October 29.
Severe frosts on the night of September 25-26 damaged grape crops in the Hawkes Bay.
A snowfall of 14cm on July 15 closed the Desert Rd and 30 motorists had to be rescued by the Army.
The road was also closed by snow or ice on August 18, and August 27.
Dr Salinger said the El Nino weather pattern was probably peaking.
"Our expectation is that it will fade by the middle of the year. Then we really have to wait and see and what the ocean basins will dish up to us."
