Tom Lee / Stuff
Two cities set new records for rainfall in July, surpassing anything MetService has recorded in the past 158 years.
It was the rainiest July in 30 years for New Zealand’s six main centers combined, at 1,316mm in gauges to date.
Two cities also recorded their wettest July since measurements began more than 150 years ago.
“It was quite exceptional in July,” said NIWA meteorologist Tristan Meyers.
“Since the beginning of winter, we have seen a regime change.”
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CHRIS SKELTON
Emmett St resident Barney Gray says she has seen only one flood like this in her 24 years of living on Christchurch Street. (Video first published July 27, 2022.)
Meyers said: Christchurch in particular was chattingwith 266 mm “and counting” rain this month.
He said it was the wettest month on record for the Garden City, and their records started in 1864 – 158 years ago.
Meyers said he wouldn’t be surprised if July turned out to be the wettest month across the country, though he was cautious about making that claim before the end of the month.
MetService data revealed that both Christchurch (267.8mm of rain) and Dunedin (140.2mm) had registered their wettest months since 1943 and 1962, respectively.
Auckland Airport recorded the second wettest July since 1962 at 250.6mm, while Hamilton Airport (211mm) and Tauranga Airport (266.1mm) both experienced their fifth wettest July.
Wellington Airport had just passed the fifth wettest of July, with 181.1 mm.
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Christchurch, in particular, has had a dip. Pictured is the flooding of the Heathcote River in St Martins, Christchurch.
MetService meteorologist Lewis Ferris said the six sites totaled about 1,316mm. “This will of course change before the end of the month.”
“The sum of these six stations this month is the largest July total in the past 30 years,” he said, “beating 2008 by 1118.8mm. It also overtook the 1,302mm recorded in May 2005 and became the month with the highest total for those six stations.”
However, Ferris warned that some years are missing monthly data, “so it’s possible there was one that could have come higher”.
Areas outside the six main centers also didn’t miss any rain, he said, although it was drier than the average July for some.
“While the six main centers represent a large proportion of the population and even more areas have received more than twice the average July rainfall, there are places that have received less than ‘normal’ rain,” he said.
“Parts of Gisborne, Hawke’s Bay, Whanganui and Fiordland are below average at this point of the month.”
Meyers said the reason for the abundance of rain this month was largely due to the… La Niña weather patternmore northerly winds, warmer than average temperatures and a “constant” supply of moisture from the subtropics.