According to NIWA, October 2015 saw a strengthening of El NiÃ±o, with the current event slightly weaker than the 1997/98 El NiÃ±o (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 NiÃ±o 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.
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.
October temperatures were above average (+0.51Â°C to +1.20Â°C) or well above average (> +1.20Â°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 0.50Â°C of average) for remaining parts of New Zealand.
As of the start of 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.
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.
* The highest temperature was 31.8Â°C, observed at Kaikoura on 7 October.
* The lowest temperature was -3.7Â°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).
– Photo: Shane Meyers