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National Institute of Water and Atmospheric Research (Niwa) senior climate scientist Georgina Griffiths said the records showed that a temperature of -25.6degC was recorded just west of Ranfurly on July 17, 1903 during "an extreme snow event".
This was 4degC colder than the -21.6degC temperature recorded on July 3 1995 at Ophir, 60km from Ranfurly, but she said the Ophir temperature was not an official record.
She said the record low was discovered as scientists went back through old records to enter them into the Niwa climate database.
"This shows that Central Otago, even recently, can get these really extreme temperatures . . . We know the early 1900s were really cold, with extremely cold spells. We know that ...
Central Otago is ... the only region of New Zealand with a continental climate.
"The chances of getting these temperatures are declining, because the weather has been getting warmer but it is important to have these long records to find those once-in-a-century events."
Project Maniototo co-ordinator Aime Pont said they were more than happy to take on the title.
"I'm sure there are many unofficial colder temperatures recorded all around the Maniototo, though." The accuracy of the temperatures had been checked against data from nearby stations and local media of the time, Mrs Griffiths said.
Ranfurly figures were collected from Eweburn, a state forest nursery just north of the Ranfurly post office, Mrs Griffiths said.