Climate Summary for July 2019

05 August 2019

New Zealand’s 2^nd-warmest July on record

Temperature	Temperatures were above average (0.51°C to 1.2°C above average) or well above average (>1.2°C above average) nearly everywhere across New Zealand, with the most unusually warm temperatures in the interior South Island and parts of Manawatu-Whanganui. Many locations observed record or near-record warm mean, mean maximum, and mean minimum July temperatures.
Rainfall	Rainfall was above (120% to 149% of normal) or well above normal (>149% of normal) for the majority of the South Island with the exception being a portion of eastern Southland and lower and interior Otago where below normal rainfall (50% to 79% of normal) was observed. For the North Island, above or well above normal rainfall was observed in central and southwestern areas while near normal (80% to 119% of normal) or below normal rainfall was observed in the majority of the north and east.
Soil Moisture	As of 31 July, soil moisture was near normal for most locations while a small area in lower coastal Canterbury and upper coastal Otago observed below normal soil moisture.

Overview

July 2019 was characterised by higher than normal mean sea level pressure east of New Zealand. Lower than normal pressure was observed in the Tasman Sea and extended over the South Island. This set up resulted in more westerly air flows than normal across the country. The distinct lack of southerly winds throughout the month and warmer than average coastal and regional sea surface temperatures contributed to unseasonably warm temperatures and New Zealand’s 2^nd-warmest July on record. A central Pacific El Niño also influenced global patterns which led to the unusual mid-winter warmth.

It has now been 30 months since New Zealand experienced a nationwide average temperature that was below average (0.51˚C to 1.20˚C below the 1981-2010 average).

The nationwide average temperature in July 2019 was 9.6°C (1.7°C above the 1981-2010 July average from NIWA’s seven station temperature series which begins in 1909).

Rainfall was variable throughout New Zealand. The majority of the South Island along with parts of central and southwestern North Island recorded above or well above normal rainfall. Rainfall totals about the upper and eastern North Island along with parts of southeastern South Island were near normal or below normal.

New Zealand’s 2^nd-warmest July on record ended on a chilly and stormy note as a wintry blast brought snow, strong winds, rain, hail, thunderstorms, and cold temperatures (refer to the highlights and extreme events section for details).

Further Highlights:

The highest July temperature was 21.6°C, observed at Wakanui on 3 July.
The lowest temperature was -6.2°C, observed at Clyde on 7 July.
The highest 1-day rainfall was 126 mm, recorded at Milford Sound on 13 July.
The highest wind gust was 169 km/h, observed at Cape Turnagain on 17 July.
Of the six main centres in July 2019, Tauranga was the warmest, Christchurch was the coldest, Dunedin was the driest and least sunny, Wellington was the wettest and Auckland was the sunniest.
Of the available, regularly reporting sunshine observation sites, the sunniest four regions in 2019 are Wider Nelson (1597 hours), Marlborough (1566 hours), Taranaki (1532 hours), and Bay of Plenty (1528 hours).