Publication Date July 25, 2017 | The Watchers

Winter storm delivers wettest day on record, New Zealand

New Zealand
Observed storm rainfall in the South Island, Friday, July 21 - Sunday, July 23, 2017. Image: NIWA
Observed storm rainfall in the South Island, Friday, July 21 - Sunday, July 23, 2017. Image: NIWA

The latest atmospheric river over New Zealand delivered one town’s wettest day on record, and broke several other long-held rainfall statistics, according to NIWA data.

Lower pressure than normal has fuelled several high impact weather events during July.

Standout statistics include:

Oamaru’s wettest day on record since daily rainfall records started in 1950. That happened on Friday (July 21, 2017) when 161.2 mm (6.34 inches) was recorded in 24 hours. The previous record was 128 mm (5.03 inches) in April 2006. In a normal July, Oamaru’s total rainfall is 40.6 mm (1.69 inches).

Following last week’s rain, winter 2017 became Oamaru's wettest winter on record and July 2017 the wettest July for the town on record.

Dunedin had its wettest July day on record since 1918 on Friday when 89 mm (3.50 inches) fell – beating the 2007 record of 75.8 mm (2.98 inches).

At Winchmore, South Canterbury, between 09:00 on Friday and 09:00 NZST on Saturday (July 22), 111.8 mm (4.40 inches) of rain was recorded – making it the 2nd wettest day on record.

Christchurch recorded 88.6 mm (3.48 inches) at the airport. Christchurch’s normal July total rainfall is 64.7 mm (2.54 inches).