Map from Google - New_Zealand

In New Zealand, divided between two main islands, the climate is oceanic, mild in the north and cool in the south, and also windy and rainy especially in the southern and western regions. The weather is often variable, so that there can be the sunshine and rain alternating in a few hours. Both the summer heat and the winter frost are rare, except in the far south, where the winter can be cold.
The rains are quite frequent throughout the year, but they are usually more frequent in winter than in summer, except in the extreme south (see Invercargill), where they are frequent even in summer.
The amount of sunshine is never exceptional, but it's still acceptable in summer, at least in the north, where there is a good number of sunny days.
Being in the Southern Hemisphere, in New Zealand the seasons are reversed compared with Europe or North America.

The North Island has a mild oceanic climate.
In Auckland, the average temperature goes from 68 °F in January and February to 52 °F in July and August. Here are the average temperatures.
Average temperatures - Auckland
Min (°F)616359555246464650525559
Max (°F)757573686359575961646872

Rainfall is fairly abundant, since it amounts to 49 inches per year, and is well distributed throughout the year; however, the rainiest season is winter, when rainfall exceeds 4 inches per month, from May to August. Here is the average precipitation.
Average precipitation - Auckland
Prec. (in)

At Auckland the temperature of the sea is very cool, however, it reaches 70 °F in February and March, when those who do not suffer from the cold, can try to swim.
Sea temperature - Auckland
Sea (°F)687070666463615959616366

The capital Wellington is located on the Cook Strait, which separates the two islands, and it's very windy. Winter is mild, given that the average temperature in July is 49.5 °F. Summer is cool: the average of January and February is 64.5 °F. Here are the average temperatures.
Average temperatures - Wellington
Min (°F)595957545046454548505257
Max (°F)707068635955545559616468

The annual precipitation amounts to 47 in, therefore it's similar to that of Auckland. The rainiest period is from May to August, which is also the one with the most frequent rains (11 to 13 days per month) and the least amount of sunshine (3/4 hours of sunshine per day). Even in summer, however, it rains an average 7/8 days per month, except in February, when the days with rain are only 6. Here is the average precipitation.
Average precipitation - Wellington
Prec. (in)

The sea temperature in Wellington is always cold, however, it reaches 63/64 °F from January to March, as can be seen in the following table.
Sea temperature - Wellington
Sea (°F)636463615957555555555761

In inland areas of the North Island, there are hills and even a mountain, Ruapehu, where you can ski in winter, and on top of which, above 8,200 feet, there are eternal snows.


The South Island is cooler, and is exposed to the westerly winds that blow for most of the year. In winter, however, snow and frost may occur, especially in the southern part, due to cold air masses of polar origin. This island is crossed by the Southern Alps, culminating in Mount Cook, 12,218 feet high: the western side is definitely wet, in fact precipitation goes from 80 to 140 inches per year along the coast, and it's even higher on the western slopes, where it touches even 20 feet of rain per year, while the eastern side, where the main cities of the island are located, is definitely less rainy, so that precipitation decrease below 39.5 inches per year, and some inland areas are even arid: in Alexandra, only 13 in of rain per year fall.

In the mountain range, there are eternal snows above 6,500 feet. In the central and southern areas of the South Island, there are glaciers that descend from the mountains almost to sea level, and after having turned into rivers, flow into the sea or into lakes.
Christchurch, located on the east coast, receives 25 in of rain per year, and is the least rainy between the major cities of New Zealand, even though the rains are quite frequent. Here is the average precipitation.
Average precipitation - Christchurch
Prec. (in)2.21.8222.62.62.821.81.822.225.4

The average temperature goes from 62.5 °F in January, to 43 °F in June and July. In this as in other cities of the eastern side, sometimes there can be sudden rises in temperature, due to downslope winds that descend from the mountains.
Average temperatures - Christchurch
Min (°F)545450453934343639434652
Max (°F)737268635754525459636670

On the western side of the South Island, winds are frequent and intense, especially in the south-west, the area of the fjords. As mentioned, we are in fact in the area of the westerly winds that sweep the southern seas around Antarctica.
In the far south, the climate is very cool, if not cold in Invercargill, where the average temperature is between 57 °F in January and 41.5 °F in July.
Average temperatures - Invercargill
Min (°F)504846433936343639434548
Max (°F)666663595450505255576164

The rains in Invercargill are frequent throughout the year, as well as wind and cloud cover. Here is the average precipitation.
Average precipitation - Invercargill
Prec. (in)

The city of Dunedin, which is located in the south-east, is a little more sheltered from rain and wind, but all in all it has a similar climate.

The coldest cities in winter are those located in the southern inland areas, such as the aforementioned Alexandra, which in addition to being dry, is also cold, with only 37.5 °F of average in July. Here, during cold waves, there may be intense frosts at night.
Average temperatures - Alexandra
Min (°F)525046393630283237414548
Max (°F)757570635548465459646872

Here the rains are frequent throughout the year but they are scarce, since they don't reach 12 inches per year. Here is the average precipitation.
Average precipitation - Alexandra
Prec. (in)

The temperature of the sea in the South Island is always cold; at Christchurch it goes from 50 °F in the winter months, to 59 °F in January to February. In the far south, in Invercargill, it reaches 55 °F in January and February, although during winter it's still about 50 °F.
Sea temperature - Invercargill
Sea (°F)555555545250505050505254

Let us now have a look at the climate of some islands belonging to New Zealand, but far away from the main territory.
Raoul Island, more than 600 miles north-east of the North Island, is mild and rainy. The average goes from 61 °F in July and August, to 70 °F in February. On average, 60 in of rain per year fall, well distributed, with a relative maximum in winter and a relative minimum in spring.
Campbell Island, 370 miles south of the southern coast, is an uninhabited island, definitely cold and windy all year round, so that the average temperature goes from 48 °F in summer to 39/41 °F in winter. Rains are frequent throughout the year, and even snowfalls in winter. The sky is almost always overcast.
The Chatham Islands, 560 miles east of the South Island, have a mild oceanic climate, similar to certain areas of the South Island itself, with frequent rainfall throughout the year, though not abundant, and an average temperature of 57 °F in January and February, and 44.5 °F in July.

New Zealand is not located in the path of cyclones, but once in a while a tropical cyclone, usually weakened, may go up to these latitudes and affect the North Island and the northernmost part of the South Island, bringing rain and wind, from November to May.

When to go

The best time to visit New Zealand is the austral summer, from December to March, which is pleasantly warm in the North Island, and cool in the South Island. Wanting to visit the country in the winter, for example in August, you can choose the North Island, being milder and more sheltered from cold waves, maybe combining the exploration of the cities with some skiing in the mountains.

What to pack

In winter (June to August): for the North Island, Auckland and Wellington, spring/autumn clothes, sweater, jacket, raincoat or umbrella. For the South Island, warm clothes, down jacket, scarf, hat, raincoat. For the high mountains, mountain clothing.
In summer (December to February): for the North Island, Auckland and Wellington, and the South Island up to Christchurch, light clothes for the day, a sweatshirt and a light jacket for the evening, raincoat or umbrella. For the south, spring/autumn clothes, sweater, raincoat and umbrella. For the Southern Alps, warm mountain clothing.