Warmth dramatically outpaces chill so far this year

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It's a story of the warm and the wet.

With 2018 already half over, the first six months of the year are telling a particularly definitive weather story of two halves.

First the warm: NIWA meteorologist Ben Noll has crunched the numbers and discovered that from January to June this year, record or near-record high mean monthly temperatures were reached a staggering 163 times. Conversely, there were just three record or near-record low mean monthly temperatures.

"In other words, for every record or near-record cold temperature, there have been about 54 warm ones."

The warm temperatures placed January to June 2018 as the 5th warmest start to any year on record, sitting behind 1998, 1937, 1999 and 2016, based on NIWA's Seven Station Series that began in 1909.

Temperatures nationwide from January to March were above or well above, while April to June temperatures were near average.

 

Jan

Feb

Mar

Apr

May

Jun

Nationwide temperature anomaly*

+3.1°C

 

+0.8°C

 

+1.3°C

 

+0.1°C

 

+0.4°C

 

0.0°C

 

*Based on NIWA’s Seven Station Temperature Series that began in 1909

January was the country’s warmest month on record, which was pushed along by the Tasman Sea and New Zealand coastal marine heatwave and La Niña’s northeasterly winds.

New Zealand has not had a month with below average nationwide temperatures since January 2017, or in 18 months.

Now for the wet.

Every main centre, with the exception of Dunedin, has had more wet days than normal. Auckland led the way with 17 more wet days than average with Hamilton close behind.

A wet day is defined as any day during which ≥1.0 mm of rain fell.

Wet days from January-June

 

2014

2015

2016

2017

2018

Average (1981-2010)

Auckland (Mangere)

46

55

58

53

78

61

Hamilton (Ruakura)

56

50

62

55

70

54

Tauranga (Airport)

48

46

63

51

61

49

Wellington (Kelburn)

61

51

52

65

60

56

Christchurch (Airport)

40

35

34

48

53

41

Dunedin (Musselburgh)

53

50

45

63

50

55

A wet day is any day during which ≥1.0 mm of rain fell

Contact:

Ben Noll, NIWA meteorologist
Ph. 09 375 6334

Research subject: Climate