Niwa analytical meteorologist and forecaster Tristan Meyers said it was a far cry from the summers of our North Island counterparts, which were exceptionally wet and cloudy, particularly Auckland, Northland, Bay of Plenty and Hawke’s Bay which each had their wettest summer on record.
But at the same time, the South Island endured extended periods of hot, dry, sunny weather — particularly in South Otago and Dunedin, which went into meteorological drought during February.
He said summer temperatures were above average (0.51degC-1.20degC) or well above average (greater than 1.20degC) across the west and south of the South Island.
New record mean air temperatures for summer were set in Greymouth (18.6degC), Franz Josef (17.5degC), Haast (16.9degC), Manapouri (West Arm Jetty) (16.2degC), South West Cape (15degC), Ōkārito (17.5degC), Oban (Stewart Island) (15.2degC), Waipounamu (Southland) (15.9degC), and Campbell Island (10.6degC).
Recording their second-highest summer mean air temperatures were Hokitika (17.9degC), Te Anau (16.3degC), Milford Sound (16.8degC), Balclutha (15.8degC), Dunedin (Musselburgh) (16.3degC) and Lumsden (15.6degC).
New records were set for the lowest summer rainfall totals at Mt Cook Airport (232mm), Balclutha (73mm), Dunedin (Musselburgh) (88mm), Windsor (63mm) and Nugget Point (102mm).
Recording its second-lowest summer rainfall total was Ōkārito (569mm), while Invercargill (155mm), Tautuku (198mm) and Campbell Island (258mm) recorded their third-lowest.
By the end of summer, soil moisture levels were well below normal across Southland, southern Otago and the upper West Coast.
Mr Meyers said the weather was in direct contrast with that of the North Island.
"That’s typical of La Nina summers. Higher-than-normal air pressure was observed to the east and south of New Zealand, with lower-than-normal air pressure to the north and west.
"This resulted in more easterly and northeasterly winds than usual, drawing in warm and humid air from the tropics and sub-tropics."
"Generally speaking, this partly explains why persistently wet and cloudy weather was experienced in northern and eastern parts of both islands, with sunnier and drier conditions in the west and south of both islands," Mr Meyers said.
"Exacerbating the warmth, humidity, and moisture availability to passing low pressure systems was a protracted marine heatwave (MHW) that peaked during January and rivalled the exceptional MHWs of 2017-18 and 2021-22.
"February sea surface temperatures were the warmest on record in the west and east of the South Island, and second-warmest on record in the north of the South Island."
December and January ranked as the 10th-warmest on record, while February ranked as the fifth-warmest.
Summer 2022-23 as a whole was the third-warmest on record.
