The deluge days were nine days between the 16th and 26th , with almost continuous rain before the downpour finally ended around 1am Tuesday morning.
June was a record-breaker of historic proportions as it also made the first six months of 2023 the wettest first half of the year since 1879.
Those six months saw 1196.7mm in Gisborne’s rain gauge — the largest amount measured in the first half of any year since 1879.
That amount of rain is more than the average total for a full year — the 30-year average (1991 to 2020) being 999.7mm.
It was a shocker of month for the whole district, coming on top of earlier weather events including cyclones Hale and Gabrielle.
As is now clear, much of the property and roading damage occurred because the district’s soils were already saturated and could not absorb any more.
The evidence is most visible in the hill country where there are the scars of fresh slips everywhere, as the ground turned to soup and trees toppled.
As might be expected the weather has had a huge depressive effect on residents, especially as day after day of low rain cloud shut out the sun.
The National Institute of Water and Atmospheric Research (Niwa) has shown the drastic effects of the weather in its daily climate maps.
Almost the whole district has had 300mm or more — and Niwa calculates from Mahia to East Cape has had some 400 percent of normal rain over the month, with soil moisture content at field capacity.
Further adding to the misery was the drastic reduction in sunshine hours — just 85 percent of normal June sunshine.
Coastal areas were greyed out to the extent that they averaged only two to three hours of sun a day.
Inland from Ōpōtiki to Wairoa fared little better, averaging only four hours of daily sun.
Most of the month’s weather was delivered from the east, with a low off the North Island prevented from moving by high pressure over the Chatham Islands.
The end of the month finally brought relief with the weather clearing, the sun returning along with very welcome drying westerlies.
One aspect that many residents have commented on is that it has not been cold, for the time of year.
Niwa’s measurements for the month indicate the mean daily temperature has been between 1.2 and 2.0 degrees warmer than average over the whole district apart from the tip of East Cape, where it has been exposed to cooler winds.
Working off data from MetService’s instruments at the airport, Gisborne’s average daily maximum temperature was around 15.4 degrees, which is only a fraction warmer than usual.
But it has been a lot warmer overnight, with the average daily minimum being just over nine degrees. That is around 3.3 degrees warmer than usual for the time of year.
Thanks to the weather, some data is missing, but overall it would appear the mean temperature for Gisborne over June was a balmy 12-plus degrees, or over one-and-a-half degrees warmer than usual.
