New Zealand has just experienced its third warmest summer on record, according to official NIWA climate figures.
NIWA’s Summer Climate Summary shows above average sea temperatures around New Zealand’s coastline were the main contributor to the warmer than average summer.
Marine heatwave conditions persisted in the Tasman Sea and coastal areas of Hawke’s Bay and Canterbury experienced marine heatwave conditions for part of summer.
The warmest summer on record was 2017/18 and the second warmest 1934/35, both of which were characterised by significant marine heatwave events.
The highest temperatures of summer were in the Bay of Plenty, Waikato and Coromandel. But the top temperature of summer went to Hanmer Forest with 38.4ᵒC on January 31 – the warmest on record for this station.
Hamilton and Tauranga went for 36 days straight without rain – both experiencing their third longest dry spell on record. Nelson had a dry spell of 40 days, its fourth longest on record.
In addition to the warm seas, summer air flow patterns also favoured warm temperatures with a distinct lack of southerlies throughout the season.
December was characterised by the prevalence of warm and moist easterly and north easterly winds, while frequents bouts of high pressure occurred in January and February. Most notably, the combination of high pressure and hot air masses originating from Australia led to prolonged hot conditions throughout much of New Zealand to the end of January. The dry and sunny weather was influenced by a central Pacific El Niño event.
Several locations across the country observed record or near record high daily maximum and minimum summer temperatures during this time.
The latter part of summer saw soils drying out making conditions severely to extremely dry in Northland, Auckland, Bay of Plenty, Waikato,Manawatu-Whanganui, Taranaki, Tasman and Nelson. Drought is now present in Nelson, Tasman and Buller.
However, summer got off to an unsettled start with frequent thunderstorms and heavy rain which caused slips and flooding around Christmas.
- Highest temperature 38.4°C, Hanmer Forest on 31 January.
• Lowest temperature -1.4°C, Tara Hills on 25 February.
• Highest one-day rainfall 200 mm, at Milford Sound on 19 January.
• Highest wind gust 182 km/h, at Cape Turnagain on 27 January.
• Sunniest spots: Richmond and Appleby – 355 hours for January, a new record.
• Of the six main centres in summer 2018, Tauranga was the sunniest, wettest and warmest, Dunedin was the coolest and least sunny, and Christchurch was the driest.