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The heat waves and floods of 2013

It may be helpful to look at what next year could bring us, so that we can be forewarned.

New Years Day kicks the year off with widespread showers in the North Island over the first three days, thence becoming mostly fine north of Taupo for most of the next two weeks. For the South Island, the first day may be wet on the West Coast and Otago/ Southland, but is mostly fine elsewhere.

Best times for holidays may be 3-19 December and 4-17 January in the northern half of the North Island, but 21-27 January for the south of the North Island. Most of December has the best camping weather for Hawkes Bay, Taranaki, the top of the South Island and southern hydrolakes.

Canterbury to the Lakes is good for the first week of January, and all of the South Island is mostly dry in the last ten days of January.

Don’t be surprised if heat-waves pass through most of NZ in the second and third weeks of January. In the last week of January heat may affect East Cape to Wairarapa and east of the South Island, and in the last week of February most of the North Island may bake, in particular East Cape.

It won't end there. East Cape to Wairarapa may suffer more unusual heat in the first week of March, with another heat spike in the first week of April. Global warming may be blamed, but closer lunar perigees during summer months will be the real reason.

The sunny summer with average rain is followed by a wet and warmer autumn (April / May). This late arrival of autumn will have weather agencies calling it an Indian summer. Farmers will be well pleased to have the extended pasture growth.

Autumn of 2013 will be remembered for its rains and flooding. These are due in the west and north of the South Island including parts of Canterbury in the first week of February; in Northland around 6 and 20 February, west of the South Island in the fourth week in March and first and last weeks in April, in the north and east of the North Island in the third week in April; and in the Bay of Plenty and the west of the North Island around the first week in May.

March and April are heavy rain months; April for most of the North Island, and March for the top and west of the South Island.

Cyclonic activity passes through the Pacific in the first and last weeks of January, the first week of February and the end of the first week of March, sending swells our way which will delight surfers. For us, the first real cyclone threat is around 12-17 March, expected to brush the north of NZ with minimal impact, but still worth heeding.

Other threats may be in the last ten days of March and around mid April; dates that planners of school trips might wish to avoid.

Unfortunately most public holidays may be wet. Waitangi Day may be wet and warm over much of the country, with heavy rain from Northland to lower North Island and lighter rain in the South Island, yet mainly fine for areas south of Oamaru.

Easter (29 March – 1 April) is not so good either, apart from Hawkes Bay and parts of Canterbury. The North Island gets a showery Good Friday, turning to rain over the lower North Island, with isolated showers elsewhere by Easter Sunday. The South Island’s Easter should be wet in the west and south with heavy rain for the West Coast but only isolated showers in eastern parts. Most skies clear by Easter Monday apart from the South Island’s West Coast.

Anzac Day may be mostly fine across the country with cold morning temperatures for dawn services and scattered frosts in sheltered districts.

A quick summary of 2013 months would be January-often dry and sunny; February - sunny and mild; March - wet with heavy rains and floods; April - warm and wet; May - sunny and mild; June - stormy; July - cold and snowy; August - cold but not very wet; September - wet South Island but dry top half of North Island; October - cloudy and wet; November - sunny but cool; and December - dry for North Island and Canterbury in second and third weeks.

The wettest day of the year for the North Island may be at or near 8 April, with torrential rains that last on and off for about a fortnight, with flooding in low-lying areas. The same happens to the South Island on 16 September and 5 and 22 December.

The 2013 ski season is not looking spectacular. Snow should first come in May (mid May in South Island, but last days of May for central North Island) and July should be the heaviest snow month. Because May and June may be warmer than usual the early snow-base won't become established.

Even July won't be much cooler than average. For the North Island the 2013 snow season could be worse than in 2012 and for the South Island probably the same as 2012 or a bit better. Really good ski seasons for all should return about 2016.

For the whole year, Auckland and Central Plateau may be the wettest regions, with Hawkes Bay the driest. In the South Island, inland Otago may be the wettest, and coastal Otago the driest.


Ken Ring of www.predictweather.com is the author of the Weather Almanac for NZ for 2013, published by Random House (NZ)