For the first time in months, no new weather records were set in the southern regions.
Rainfall was below average and temperatures were above average, but not enough to break any records.
In fact, it appears as though September 2022’s weather was simply average.
Niwa climate scientist Gregor Macara said the month was characterised by higher than normal mean sea level pressure (MSLP) over all of New Zealand, but especially near the South Island.
"This produced more easterly airflow than normal in the South Island.
"The prominence of high pressure systems over and near the South Island deflected moisture-bearing low pressure systems off towards the north of the country."
He said the observed MSLP patterns for the month were associated with a continuation of a moderate La Nina event, and a positive southern annular mode (SAM).
"The SAM is a proxy for the location of a belt of westerly winds that encircle the Southern Ocean and occasionally protrude into the mid-latitudes.
"Usually, a positive SAM can indicate calmer and drier conditions for New Zealand, and this was certainly the case for most of the South Island."
Mr Macara said rainfall was below normal or well below normal for most of the South Island and Stewart Island, and temperatures were near average for Otago and inland Southland.
"The exception was areas of coastal Southland and the West Coast, where temperatures were above average.
"Overall, the nationwide average temperature in September 2022 was 11degC.
"This was 0.4degC above the 1981-2010 September average, making it New Zealand's 19th-warmest September since Niwa’s seven station temperature series began in 1909."
