Autumn starts drier, cooler than normal after Northland’s wettest summer on record

March was drier and colder than normal, coming after Northland experienced its wettest summer on record. Kevin Wigmore captured this Bream Bay sunrise on a chilly March morning.

After its wettest summer season on record, autumn started out far drier, and a bit cooler, than normal in Northland.

And the rest of autumn, and leading into winter, is expected to be a bit different, with Niwa saying the rest of the season is expected to see temperatures above, or near normal, while rainfall is expected to be near, or above average.

Whangārei recorded more than a metre of summer rain and December through to February produced some of the heaviest downpours on record in the region, according to the Niwa Climate Summary for summer.

The city recorded a whopping 1004mm of rain for the three summer months - just under four times the normal summer average and the highest summer total since records began in 1937.

Whangārei also recorded its highest-ever single summer day rainfall total when 216mm fell in the district on February 12. It recorded over 77 per cent of its annual normal rainfall during summer.

Kerikeri recorded its second wettest summer on record with 767mm - just over twice the normal summer rainfall - and Russell had its fourth highest summer rainfall with 624mm - again, just over twice the summer norm.

But autumn has started off far drier and a bit cooler than usual, the Niwa monthly climate summary for March shows.

Niwa Climate Scientist Gregor Macara said March was characterised by lower-than-normal mean sea level pressure (MSLP) with numerous low-pressure systems tracking in from the Tasman Sea during the month.

‘’After three consecutive years of La Niña, ENSO neutral conditions developed during March, and much of the country observed more frequent westerly winds than normal. Sea surface temperatures in New Zealand’s coastal waters remained higher than average during March, and were the warmest on record for the month of March to the east of the South Island,’’ Macara said.

He said March rainfall was below normal (less than 50-79 per cent of normal) or well below normal rainfall (less than 50 per cent of normal) in Northland, Auckland, northern Waikato, coastal Bay of Plenty, Gisborne, northern Wairarapa and Nelson.

March temperatures were also below average (0.51-1.20C below average) in parts of Northland, Auckland, Waikato, and the Ruapehu District.

‘’March was a dry month for the upper North Island, with rainfall events few and far between. It was especially dry in Russell which received just 8mm of rain - just 7 per cent of the March normal - making it the town’s third-driest March since records there began in 1919,’’ he said.

‘’Whangārei recorded 17mm of rain (14 per cent of the March normal), while Kaitaia, Kerikeri and Dargaville each received less than a third of their normal March rainfall.’’

When it came to temperatures, Whangārei had its lowest-ever March minimum air temperature. On March 30 the district recorded a low of 4.2C, the lowest since records began. On March 31, Kerikeri recorded its third lowest daily temperature since records began there in 1945 with 4.9C.

The nationwide average temperature in March 2023 was 15.9C. This was 0.1C above the 1991-2020 March average from NIWA’s seven-station temperature series which begins in 1909. The highest temperature recorded for the month was 30.5C at Akaroa on March 2.

Niwa predicted that in Northland, for the next month and a half, temperatures are equally likely to be near average or above average (a 45 per cent chance each) while rainfall totals are most likely to be near normal (a 45 per cent chance) or above normal (20 per cent chance). A period of northerly winds in late April may increase the chance for heavy rainfall. Rainfall may tend lower than normal during early winter as southerly winds may become more common.