Niwa climate scientist Gregor Macara said it was particularly wet in Oamaru and at Dunedin’s Musselburgh weather station, where more than four times the normal October rainfall was recorded.
‘‘It was a very wet month for many parts of the South Island, with 24 locations observing record or near-record high October rainfall totals.
‘‘Dunedin and Oamaru each observed their wettest October on record, with 406% and 424% of their normal October rainfall, respectively.
‘‘Dunedin’s monthly rainfall total of 244mm is approximately one-third of its normal annual rainfall.
‘‘A large portion of Dunedin’s rainfall occurred during a single event on October 3-4, which led to widespread flooding and a local state of emergency being declared.’’
Dunedin’s record is the highest since its records started in 1918, he said.
Other areas recording their highest October rainfall totals were Lake Tekapo (158mm), Pukaki Airport (148mm), Waimate (149mm), Dunedin Airport (171mm), Lumsden (195mm) and Tautuku (260mm).
Middlemarch (125mm), Cromwell (77mm), Balclutha (199mm) and Nugget Point (152mm) recorded their second-highest October rainfalls.
On October 3, the rain was so heavy, an October extreme one-day rainfall record was set at Dunedin’s Musselburgh station when 131mm fell in 24 hours.
Oamaru (82mm), Dunedin Airport (55mm), Balclutha (73mm), Nugget Point (43mm) and Tautuku (89mm) recorded their second-highest October one-day rainfalls; and Milford Sound (292mm), Lumsden (42mm) and Clyde (27mm) recorded their third-highest.
As a result, soil moisture levels were higher than normal across northern Southland, Otago and much of Canterbury by the end of the month.
Mr Macara said no temperature records tumbled in the southern regions, despite the mercury being above average or well above average in eastern Canterbury, the West Coast, Fiordland and eastern parts of Otago; and near average in inland parts of south Canterbury, inland Otago, and central and southern Southland.
The month had more easterly airflows than normal over the lower South Island.
The nationwide average temperature in October 2024 was 12.9°C, 0.8°C above the 1991-2020 October average.
