Climate Summary for October 2015

A dry month for most and warm for the eastern South Island.

Rainfall

 

Rainfall was below normal (50-79%) or well below normal (< 50%) for the majority of the North Island, as well as northern, eastern and inland parts of the South Island north of Otago.  Conversely, rainfall was above normal (120-149%) or well above normal (> 149%) for south-eastern parts of the South Island, Fiordland and southern Westland.

Temperature

October temperatures were above average (+0.51°C to +1.20°C) or well above average (> +1.20°C) throughout the South Island, with the exception of the West Coast.  Similarly, temperatures were above average in parts of Auckland, Bay of Plenty, Gisborne, Hawke’s Bay and the Kapiti Coast.  Temperatures were typically near average (within 0.50°C of average) for remaining parts of New Zealand. 

Soil Moisture

As of 1 November 2015, soil moisture levels were typically below normal for much of the North Island, as well as for most eastern, inland and northern parts of the South Island.  The notable exceptions were northern Wairarapa and the south-eastern South Island where soil moisture levels were above normal for the time of year.

Sunshine

A sunny October for eastern and southern parts of the North Island as well as eastern and central areas of the South Island, with above normal (110-125%) or well above normal (> 125%) sunshine recorded in many of these areas.

Overview 

October 2015 saw a strengthening of El Niño, with the current event slightly weaker than the 1997/98 El Niño (the strongest since 1950) at this stage.  The month was characterised by air pressures which were higher than normal over southern Australia, the Tasman Sea and New Zealand and lower than normal to the south-east of New Zealand.  This resulted in more south-westerly airflows over New Zealand than is normal for the time of year.  This southwest flow anomaly (typical of El Niño at this time of year) was clearly illustrated by the rainfall anomalies observed across New Zealand for October.  Areas sheltered from the south-westerlies received below normal (50-79%) or well below normal (< 50%) rainfall, and this was the case for the majority of the North Island, as well as northern, eastern and inland parts of the South Island north of Otago.  In contrast, rainfall was above normal (120-149%) or well above normal (> 149%) in areas exposed to the south-west, including south-eastern parts of the South Island, Fiordland and southern Westland. The contrast between areas of below normal and above normal rainfall was notable, with relatively few locations receiving near normal rainfall (within 20% of normal) for the month. 

Soil moisture levels largely resembled the rainfall anomalies observed throughout New Zealand during October.  Specifically, as of 1 November 2015 soil moisture levels were below normal for much of the North Island, as well as for most eastern, inland and northern parts of the South Island.  In contrast, soil moisture levels were higher than normal in northern parts of coastal Wairarapa and the south-eastern South Island around eastern Southland and southern Otago.  Soil moisture levels were near normal for the time of year the West Coast and remaining parts of Southland.

October temperatures were above average (+0.51°C to +1.20°C) or well above average (> 1.20°C) for most of the South Island, except the West Coast where temperatures were near average (within 0.50°C of the October average).  Temperatures were also above average in parts of Auckland, Bay of Plenty, Gisborne, Hawke’s Bay and the Kapiti Coast, with near average temperatures for remaining parts of the North Island. The nation-wide average temperature in October 2015 was 12.7°C (0.6°C above the 1981-2010 October average from NIWA’s seven station temperature series which begins in 1909)[1].

October sunshine was abundant for eastern and southern parts of the North Island as well as eastern and central areas of the South Island, with above normal (110-125%) or well above normal (> 125%) sunshine recorded in many of these areas.  Sunshine hours were near normal (90-109%) for most remaining areas of the country.  Record or near-record high sunshine hours for the month were observed in ten locations from as far south as Balclutha to as far north as Kaitaia.

Further Highlights:

  • The highest temperature was 31.8°C, observed at Kaikoura on 7 October.
  • The lowest temperature was -3.7°C, observed at Pukaki Aerodrome on 26 October.
  • The highest 1-day rainfall was 291 mm, recorded at Milford Sound on 16 October.
  • The highest wind gust was 172 km/hr, observed at Cape Turnagain on 5 October and South West Cape on 7 October.
  • Of the six main centres in October 2015, Auckland was the warmest, Christchurch was the coolest, driest and sunniest, Dunedin was the wettest and Hamilton was the cloudiest.
  • Of the available, regularly reporting sunshine observation sites, the sunniest four locations so far in 2015 (1 January to 31 October) are: Blenheim (2239 hours), Whakatane (2212), Appleby (2189) and Lake Tekapo (2149 hours).

Download the full Climate Summary for October 2015 [543KB PDF]

Climate Statistics for October 2015 [76 KB]

Contact

For further information, please contact:

Mr Chris Brandolino
NIWA Forecaster – NIWA National Climate Centre
Tel. 09 375 6335, Mobile (027) 886 0014



[1] Interim value