A load of hot air
Manawatu¯ and Horowhenua temperatures last year set all sorts of records thanks to hot air from the north.
However, the year ended with an unwanted Christmas present for Palmerston North residents to put a dampener on things.
In its annual climate summary released this week, Niwa revealed just how hot 2018 was.
Although the national average temperature was the secondwarmest since 1998, at 13.41 degrees Celsius, that was only 0.8C above the average for the past 30 years.
However, Levin and Palmerston North were 1.4C and 1C above the average, respectively.
Levin’s average temperature was 14.4C – the highest ever for the town – while Palmerston North recorded its second-highest ever average of 14.3C.
Niwa principal scientist Chris Brandolino said it was all to do with hot air. The year was dominated by winds coming from the north and northeast, which would travel over the Ruahine and Tararua ranges before hitting Manawatu¯ and Horowhenua, Brandolino said.
The air going down resulted in a warming effect that, combined with cloud cover, would hold temperatures higher for longer.
That could also explain why the area had higher-than-average minimum air temperatures, he said.
Levin only got down to 21.2C on February 12, the highest ever minimum temperature on that day since records began.
Palmerston North, meanwhile, had an average minimum temperature of 9.9C, That was 0.9C above average and the thirdhighest average on record.
Levin also managed to set its third-highest ever daily temperature on January 29, when the mercury hit 30.9C.
Brandolino said warmer-thanaverage sea temperatures at the start and finish of 2018 might also have played a part.
Palmerston North did set an unenviable record on Christmas Day, though. The 79 millimetres of rain that fell, contributing to surface flooding in some areas, was the most ever on Christmas Day.