‘Fingerprints’ over warmest November

This past November was the warmest on record, with temperatures well above average – more than 1.2 degrees Celsius higher than normal.

Warm, humid northeasterly winds from the subtropics combined with well above average sea surface temperatures surrounding the country, warming the country. The pattern was associated with a developing La Nina climate system, and is responsible for predictions of a warmer than average summer ahead.

Overall, the nationwide average temperature in November was

15.4C (1.7C above the 1981–2010 average), making it our warmest November since Niwa’s sevenstation temperature series began in 1909.

It surpassed November 2019 as the warmest on record, and three of the four warmest Novembers have now occurred since 2013.

The season as a whole was the second-warmest spring on record. Temperatures were above average across nearly all of the North Island and a majority of the South Island, and well above average in the Bay of Plenty.

Twenty-six locations experienced the highest or second-highest warmest temperatures for spring on record. Notably, in Hamilton (Ruakura) it was the warmest spring since 1906, a product of high daytime temperatures combining with a warm night.

No locations experienced record or nearrecord low spring temperatures.

Niwa forecaster Nava Fedaeff said the ‘‘fingerprints of climate change were all over’’ this report. ‘‘We know our climate

has warmed. We know that that’s the reason we had our warmest November on record, and we know cool records are really rare.’’

According to the report, there was less rain than usual (50 to 79 per cent of normal) in parts of Wellington and Wairarapa, eastern Marlborough, and coastal northern and central Canterbury.

Akaroa received only 60 per cent of normal spring rainfall, making it the 4th-driest spring since records began in 1977.

Above normal rainfall (120 to 149 per cent of normal) was observed in much of Northland, northern Auckland, Gisborne and northern Hawke’s Bay, northern Tasman and interior Otago. It was the wettest spring on record in Kerikeri with records extending back to 1935.

‘‘Extreme rainfall events, like in Gisborne this spring, and in Christchurch and the West Coast in winter, those are in line with climate change expectations.’’

Gisborne experienced its second-wettest spring since 1905.

More than half of the seasonal rainfall fell over just a few days at the start of November and led to a State of Emergency declaration.

‘‘We know our climate has warmed . . . and we know cool records are really rare.’’ Nava Fedaeff Niwa forecaster