Dry month for Timaru in May, next three months to be normal says Niwa

Niwa says May was a particularly dry month in Timaru, where just 9mm of rainfall was recorded. (File photo)
MYTCHALL BRANSGROVE/STUFF
Niwa says May was a particularly dry month in Timaru, where just 9mm of rainfall was recorded. (File photo)

Timaru recorded just 9mm of rainfall in May but it wasn't record-breaking.

National Institute of Water and Atmospheric Research (Niwa) scientists said in a report released on Wednesday that May had a warm and dry start, which was followed by cooler and unsettled conditions.

Rainfall was well below normal for coastal South Canterbury and the 9mm recorded compares to the record low for May of 2.4mm in 2015 and the 13mm which fell in May 2017.

South Canterbury Federated Farmers president Jason Grant says having normal rainfall for the next few months would be positive for farmers. (File photo)
JOHN BISSET/STUFF
South Canterbury Federated Farmers president Jason Grant says having normal rainfall for the next few months would be positive for farmers. (File photo)

Niwa's average monthly rainfall figure for Timaru in May, recorded from 1981 to 2010, is 47mm.

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Further south, Oamaru recorded 19mm of rainfall in the month.

Niwa climate scientist Gregor Macara said while the dry conditions in Timaru weren't record-breaking, having such little rainfall was notable.

"Partly why they've had such little rainfall was because they've had a lot of west and south-west winds.

"Most of those rain-bearing fronts weren't able to make their mark or impact on Timaru."

Niwa's seasonal climate outlook for June to August says temperatures in coastal Canterbury and east Otago are likely to be near average or below average.

Macara said the outlook for the eastern South Island for the next three months, including Timaru, was for normal or near-normal rainfall.

"Essentially the least likely outcome is for it to be dry during that three month period.

"At this stage I would expect that there's going to be more moisture or rainfall this month compared to May based on the guidance we have at the moment.

"It looks like this month there will be low air pressures in the north of New Zealand which can bring heavier rain events to the eastern North Island and even South Island as well."

South Canterbury Federated Farmers president Jason Grant said having normal rainfall for the next few months would be positive for farmers.

"An average rainfall would be better than having a really wet winter."

Grant said they noticed it was drier than normal in May.

"Obviously at that time of the year we don't get a lot of growth so having it a bit drier was an advantage.

"It's probably helped a few cropping farmers to get some of their crop in the ground being a bit drier in May as well.

"March and April were quite wet so we definitely noticed it was a bit drier."

According to the monthly report, the lowest temperature in the country last month was -8.8 degrees Celsius, recorded at Mt Cook Airport on May 31.

Lake Tekapo's maximum air temperature on May 31 of just 0.1C was its third-lowest maximum ever.

Towards the end of the month, the report says settled weather under high pressure conditions saw inversions established through many inland valleys and basins in the South Island.

"Overall, mean sea level air pressures were much lower than normal to the south of New Zealand during May.

"However, during the second half of May, a blocking anticyclone became established over the southeast of Australia.

"Many fronts were embedded in this flow, which resulted in an unsettled spell of weather with bands of thunderstorms throughout the country.

"A weak ridge of high pressure covered the lower South Island during the final days of last month, bringing heavy frosts to parts of the Mackenzie Basin, Central Otago, and Southland."

The nationwide average temperature last month was 11.2C.

The Timaru Herald