Lying between 34°S and 47°S, New Zealand is squarely in the 'Roaring Forties' latitude - meaning it has a prevailing and continual wind blowing over it from west to east, ranging from gentle freshening breezes to occasional raging winter gales. Coming across the Tasman Sea, this breeze is relatively warm and moisture-laden. When it hits New Zealand's mountains the wind is swept upwards, cools and drops its moisture. When the wind comes from the south it's from Antarctica and is icy and cold; a southerly wind always means cold weather.

The South and North Islands, because of their different geological features, have two distinct patterns of rainfall.

In the South Island the Southern Alps act as a barrier for the moisture-laden winds coming across the Tasman Sea. This creates a wet climate on the western side of the mountains and a dry climate on the eastern side; annual rainfall is more than 7500mm in parts of the west but only about 330mm across some of the east, even though it's not far away.

The South Island's geography also creates a wind pattern in which the prevailing wind is swept upwards, cools and looses its moisture in the form of rain or snow, then blows down onto the Canterbury Plains as a dry wind. It then gathers heat and speed as it blows downhill and across the plains towards the Pacific coast. In summer this wind can be very hot, dry and fierce. Called a katabatic wind, it is similar to other famous mountain-influenced winds in the world, including the Chinook wind formed by the Canadian and USA Rockies. In the Grey valley, on the South Island's west coast, is another kind of downhill wind, locally called 'the Barber'.

In the North Island, the western sides of the high volcanoes also get a lot more rain than the eastern sides, although since there's no complete barrier (as there is in the Southern Alps) the rain shadow is not as pronounced. Rainfall is more evenly distributed over the North Island, averaging around 1300mm per year. In the North Island rain falls throughout the year; typically, rainy days alternate with fine days, which is enough to keep the landscape perennially green.

It is a few degrees cooler in the South Island than the North Island, and of course it's colder in winter (June, July and August) than in summer (December, January and February). There are several regional variations. It's quite warm and pleasant in Northland (the far north of the North Island) at any time of year; it's almost always a few degrees warmer than the rest of the country. Higher altitudes are always considerably cooler, and it's usually windy in Wellington, which catches winds whisking through Cook Strait in a sort of wind tunnel from the Tasman Sea to the Pacific Ocean.


O Whangarei



Hauraki Gulf



Bay of Plenty

O Rotorua

O Gisborne

New Plymouthp

Hawke Bay


Wanganui 0

Palmerston North




Westport O


Creymouth O



Haast O


Oamaru dunedinO

O Invercargill

Oban O

Stewart Island (Rakiura)

NEW PLYMOUTH 6m(20ft) c "F Temp/Humidity * in Rainfall

WELLINGTON i28m(420ft) c "F Temp/Humidity * in Rainfall

NELSON 5m(16ft)

c "F Temp/Humidity


CHRISTCHURCH 34m(ll2ft) ,3

•c "F Temp/Humidity *

in Rainfall m


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QUEENSTOWN 335m<1116ft)

"T "F Temp/Humidity r m Rainfall

QUEENSTOWN 335m<1116ft)

"T "F Temp/Humidity r m Rainfall

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