Autumn 2019

New Zealand’s 4th-warmest autumn on record. 

Temperature 

It was New Zealand’s 4th-warmest autumn on record. Temperatures across the country were mostly above average (+0.51°C to +1.20°C of the autumn average) or well above average (>1.20°C of the autumn average) while few locations experienced temperatures which were near average (-0.50° to +0.50°C of the autumn average).

Rainfall

Rainfall totals over much of the North Island were below normal (50-79% of the autumn normal) with isolated pockets of well below normal (<50 % of the autumn normal). The exceptions to this were part of Bay of Plenty and western parts of the Wellington and Manawatu-Whanganui where near normal (80-120% of the autumn normal rainfall) rainfall totals were observed, and in the Taranaki region where rainfall was near to above normal (120-149% of the autumn normal). A large portion of the South Island observed above or well above normal rainfall (>120% of the autumn normal), including West Coast, much of Southland, western parts of Canterbury and Otago, as well as Nelson and northern Marlborough. Remaining parts of the South Island were largely near average with pockets of below average rainfall occurring throughout.

Soil moisture

By the end of autumn 2019, soils were drier than normal for much of the North Island with small areas of wetter than normal soils about western Waitomo and the Kapiti Coast. South Island soil moisture was generally near normal with pockets of below normal soil moisture about Waimate and Waitaki as well as interior Marlborough region.

Overview

Autumn 2019 was characterised by higher than normal mean sea level pressure over and to the east of New Zealand, resulting in more northerly winds than normal across the country. This, in combination with warmer than average sea surface temperatures around New Zealand coastlines resulted in autumn temperatures which were above (+0.51°C to +1.20°C of the autumn average) or well above average (>1.20°C of the autumn average) for the time of year over most of the country.

The nationwide average temperature for autumn 2019 was 14.4°C (1.17°C above the 1981-2010 average from NIWA’s seven station temperature series which begins in 1909) making it the 4th-warmest autumn on record in New Zealand, and only 0.02°C cooler than the autumn of 1999, the 3rd-warmest autumn on record.

Autumn 2019 got off to a warm start during March with above to well above average temperatures experienced across the country. This was the equal 2nd-warmest March on record and many locations observed record or near-record warm mean, mean maximum or mean minimum temperatures during this time. The warmest autumn temperature of 32.4°C was recorded in Waipara West on 5 March. Temperatures during April were largely near average (-0.50° to +0.50°C of average) for the time of year and the lowest autumn temperature of -6.0°C was observed at Ranfurly on 7 April. The season ended on a warm note with New Zealand experiencing its 3rd-warmest May on record. Many locations also observed record or near-record warm mean, mean maximum or mean minimum temperatures during this month.

In terms of rainfall, much of the North Island experienced below normal (50-79% of normal) or well below normal (<50% of normal) levels during March and May whereas April was more variable with below to well below normal rainfall occurring in the south and west. Rainfall anomalies in the South Island also varied spatially during the individual months of autumn ranging from well below normal (particularly in the west and north) to well above normal (>149% of normal). Parts of the West Coast and western Canterbury through to western Otago observed well above normal totals for all three months of autumn. Extremely heavy rainfall occurred in the western South Island between 25-27 March resulting in flooding, the collapse of the Waiho Bridge near Franz Josef, and the declaration of a State of Emergency in Westland (refer to the highlights and extreme events section for further details). The highest 1-day rainfall was 401 mm, recorded at Milford Sound on 25 March.

Further Highlights:

  • The highest temperature was 32.4°C observed in Waipara West on 5 March.
  • The lowest temperature was -6.0°C, observed at Ranfurly on 7 April.
  • The highest 1-day rainfall was 401 mm, recorded at Milford Sound on 25 March.
  • The highest wind gust was 196 km/h, observed at Cape Turnagain on 15 May.
  • Of the six main centres in autumn 2019, Auckland was the warmest, sunniest and driest, Christchurch was the coolest and least sunny, and Wellington was the wettest.

Download

Climate Summary for Autumn 2019 [PDF 0.5MB]

Contact

Principal Scientist - Forecasting and Media
Research subject: Climate