The softer deposits are dug into gullies and valleys, while the more resistant lava flows form the protruding ribs that stretch down the sides of the mountain. See also Volcanoes in New Zealand Climatic conditions Isolated in an otherwise low land and open to the weather conditions in all directions, Mt Taranaki creates its own climatic conditions. Its slopes are among the wettest in the North Island. However, while the mountain experiences 166 days of rain annually, it also receives 2110 hours of sunshine, resulting in plenty of fine weather. The weather is very changeable and difficult to predict.
Temperatures can drop very rapidly and in winter soft snow can turn into ice in a matter of minutes.
Vegetation Vegetation in Egmont National Park has two sets of distinctive characteristics that are the result of having developed on a tall, isolated volcano. The first of these characteristics is that the change in plant types and associations with altitude is especially clear, in a series of zones that surround the mountain from sea level to the summit. As altitude rises the giant podocarps become rarer and kamahi dominates, their trunks and branches often covered in mosses, liverworts and filmy ferns. They are thought to have colonised from either Ruapehu or the mountains of Nelson and Marlborough, before evolving specific characters in isolation. This is thought to be the consequence of the limited dispersal power of beech seeds, which did not allow the species to re-colonise the mountain after destruction by volcanic events.