A calm, sunny climate
Nelson vies with Marlborough (and in some years Bay of Plenty) for the honour of having the country’s highest sunshine hours – and usually wins. One year the region recorded over 3,000 hours of bright sunshine, but the annual average is around 2,400 hours. Coastal Golden Bay – less sheltered from Tasman Sea weather systems – gets around 200 hours less.
Nelson’s climate is sometimes dubbed ‘Mediterranean’, but this is not strictly true, as a Mediterranean climate is characterised by wet winters and hot, dry summers. In Nelson, winters are only slightly wetter than summers.
Nelson is one of the country’s calmest cities – one in four days is calm (average winds of less than 3.6 kilometres/hour). The predominant winds are northerly or north-easterly sea breezes, followed by south-westerlies. Mountains form a horseshoe to the east, west and south, protecting the region from bad weather. South-westerly winds have to travel across the entire South Island before reaching the region, so they seldom bring rain. Only northerlies tend to bring widespread cloud cover. Maximum daytime temperatures are typically 20–26°C in summer and 10–15°C in winter.
The north coast has a milder climate than the inland valleys, which experience intense winter frosts and fogs. The Waimea Plains often have summer droughts, while the mountains of north-west Nelson can be very windy. In general it is wetter in the west and drier in the east, and much cooler and less sunny in the mountains. The sea’s moderating effect on temperatures does not extend very far inland.
A long time dying
Former nurse Bridget Ristori remembered Nelson being promoted for its health-giving climate. ‘In early days emphasis used to be placed on the suitability of the climate for invalids, and only the other day I was talking to a particularly healthy man of 92, who had been sent out here to die when he was 24.’1
Protected areas and natural history
The region has three national parks – Abel Tasman (created in 1942), Nelson Lakes (1956) and Kahurangi (1996), New Zealand’s second-largest. There are three marine reserves, at Whanganui Inlet on the western coast, in Tasman Bay between Glenduan and Ataata Point, and at Tonga Island off the coast of Abel Tasman National Park.
The eastern inland ranges, such as those in Nelson Lakes National Park, are largely greywacke and form distinctive scree slopes which resemble Canterbury’s mountain landforms. Mt Franklin, at 2,340 metres, is the highest point in the region. North-west Nelson’s mountains are lower than the mountains further south, so they were not as heavily glaciated in recent ice ages and have acted as a refuge for many species. Isolated alpine areas have considerable diversity in plants and invertebrates (animals without backbones). For example, the land-snail genus Powelliphanta reaches its greatest species diversity in Kahurangi National Park (although these snails are absent from the central mountains, which were most glaciated).
Bird species in Kahurangi include the whio (blue duck) and great spotted kiwi, and the park is home to long- and short-tailed bats (New Zealand’s only native land mammals). There are also life forms adapted to living in the region’s caves, such as the Nelson cave spider, the country’s largest native spider in terms of leg span. At Farewell Spit, 112 bird species have been recorded – the spit sees great migrations of knots, godwits, Mongolian dotterels, curlews, little whimbrels, grey-tailed tattlers and turnstones. It is also known for whale strandings – in 1991, 325 whales came ashore.
Lowland soils are generally poor, with some fertile pockets. Coastal Nelson links cooler-climate South Island vegetation to the more temperate lowland-forest species of the North Island. Tawa reaches its south-western limit in lowland Tasman and Golden Bay. Kawaka, usually a North Island plant, is also found in western Golden Bay. Whau, which provided Māori with light wood for net floats, grows in frost-free pockets of Tasman Bay and Golden Bay, but is otherwise a coastal North Island tree.
Before Pākehā settlement, forest grew to the shore, although Māori had burnt off areas in the Waimea Plains and Motueka valley. Today, the lowland forests and swamps have been heavily reduced. Beech forests remain in the mountains, where the vegetation’s biodiversity is remarkable. Some 80% of the country’s native alpine plant species grow in north-west Nelson, with many species found nowhere else. While the alpine plants in Nelson Lakes National Park are similar to the rest of the South Island, those in Kahurangi National Park have affinities with both North and South island alpine vegetation.