New Zealand has a temperate maritime climate, characterized by warm summers, cool winters, as well as regular precipitation all year round. There are four seasons: Summer in December to February and Winter in June to August (the opposite of the Northern Hemisphere). The country’s geography creates about 10 distinct climatic regions, ranging from the subtropical north of Auckland to the continental and semi-arid area in central Otago.
The mountain ranges along New Zealand’s northeast-southwest axis form a barrier to the strong prevailing westerly winds-often referred to as the roaring forties. Moist air hitting the mountains is pushed up and cooled, with the moisture falling back to the west as rain. As a result, more than average rain falls in the western half of the country and less than average in the eastern half. In the South Island, this effect tends to be the strongest, with the Southern Alps. On the west coast, they receive between 2000-7000 mm of precipitation annually, compared to only 500-800 mm on the Canterbury and Otagoin coasts in the east. Most other places receive between 600 and 1600 mm per year on average. In the north and central parts of the country, it is generally drier in summer. In the south, it is generally drier in winter.
Daily summer highs average between 17 ° C and 25 ° C. Daily winter highs average 7 ° C to 16 ° C and nighttime lows average -3 ° C to 8 ° C. The warmest temperatures are generally found in the north and east of both islands, while the coolest temperatures are generally found in the interior of both islands and on the southern South Island. Sunshine hours are highest in the Bay of Plenty, Nelson Bays and Marlborough.
Snow is found mainly in the mountainous parts of the country and in some inland areas, and may occasionally close mountain passes and high roads in winter. In the eastern and southern parts of the South Island, snow may fall to sea level every 1-2 years. Snow on the western South Island and coastal North Island is rare. Wellington brings snow to sea level on average every 40-50 years. The unprotected areas of the country can get a bit windy especially in the center through the Cook Strait and around Wellington.
The weather in New Zealand is very changeable, and even in summer you can get all four seasons in one day. Be prepared for the weather to change from good to showers (and vice versa) without notice.