Rotorua has already had more rain than it would normally get in a year and, with more on the way, the city may break a 50-year-old record.
So far this year, the city has had 1825mm of rain, more than the normal annual total of 1513mm, according to weatherman Brian Holden. The highest annual rainfall of 2047mm fell in 1971. Last month, Rotorua had 195mm of rain, compared with the usual October total of 125mm.
Mr Holden said current rain patterns were showing no signs of change and the annual rainfall could reach or exceed the record.
In October, it did not rain on only eight days and the highest amount, 38mm, fell on October 11. On October 3, when 36mm fell, the city experienced thunderstorms and the strongest wind gusts for the month - 55km/h (30 knots).
October was also a very warm month, with maximum temperatures of between 20C and 23.4C on nine days. Mr Holden said 23C was "unseasonably hot" for October.