New Zealand is a relatively small area of land with a temperate climate, lying in the roaring forties wind system. The ocean, prevailing winds and mountains greatly influence the climate.
Full story by Brett Mullan, Andrew Tait and Craig Thompson
Main image: A pond in Ōhariu Valley, Wellington, during a drought
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The climate is the long-term weather pattern of a country or region. When describing the climate you would include average rainfall and temperatures, types of wind, and whether there are often floods, cyclones or droughts.
New Zealand’s climate
Strong westerly winds race across the open Pacific Ocean, and quickly pass over New Zealand’s small land mass. They bring rain, and frequent changes in the weather.
In Auckland and other northern regions there are lighter winds and calmer, warmer weather. In regions further south, such as Wellington, or Canterbury or Southland in the South Island, it is cooler, and the winds are generally stronger.
New Zealand’s climate is fairly mild, compared to countries that have weeks or months of extreme heat or cold.
Westerly winds and the mountains
The Southern Alps run along the West Coast of the South Island. When westerly winds rush across the ocean to New Zealand, they meet the alps and rise up over them. The air gets colder when it gets higher, and the cold makes moisture in the air form raindrops. These fall onto the West Coast. Then the air passes to the other side of the mountains, carrying no more rain. So the West Coast is very wet, and the east is quite dry.
This also happens when winds hit the mountain ranges in the North Island.
Sunshine and temperatures
Most of the country has a lot of sunshine – at least 1,800 hours a year. Average temperatures range from 10°C in the south to 16°C in the north. New Zealand’s temperatures increased about 0.7°C during the 20th century.
Rain and snow
It rains often in New Zealand. Most areas have 600–1,600 millimetres of rain a year. The northern and central areas have more rain in winter, than in summer.
Most snow falls in the mountain areas, and there is often snow in the south and east of the South Island in winter.
With global warming, New Zealand’s glaciers have got smaller. There is less snow in the mountains and the sea level has risen 14–17 centimetres.
Climate in different regions
- The far north has subtropical temperatures.
- The far south can be very cold in winter, with severe conditions in the mountains.
- The West Coast of the South Island is the wettest area.
- Marlborough, Canterbury and Otago, east of the Southern Alps, are the driest.
Global changes in climate
New Zealand’s westerly winds are getting stronger. This may be caused by global warming.
The El Niño weather pattern affects New Zealand, as well as other countries. It follows a 3–7 year cycle, with two different phases:
In the El Niño phase
- south-westerly winds are stronger
- temperatures are lower
- the north-east of the country is drier.
In the La Niña phase
- winds are mainly north-east
- temperatures are higher
- the north and east of the North Island are wetter
- there may be drought in the South Island.