The environment ministry has opened up detailed new climate projections to the public.

The Ministry for the Environment is hosting a web page using NIWA data, which allows users to see climate projections for every five km2 of the country, apart from the Chatham Islands.

Anyone can visit the public database and select whether they are interested in drought, rainfall, wind or temperature, which season they are interested in and whether they would like to see projections for low, medium or high greenhouse gas emissions.

The ministry says councils, iwi and businesses will be able to use the data to prepare for climate change in their communities, for example to see what average temperatures might look like in Invercargill in 50 years, or how much rainfall could might be expected in Taranaki by 2100.

The move was welcomed by the Sustainable Business Council, which said getting access to robust climate data could be a challenge.

Many large companies now have to publish reports to investors on how different climate scenarios might affect their business.

Dr Andrew Tait, Chief Scientist for Climate, Atmosphere and Hazards at NIWA, said the agency's supercomputer "ran hot for 12 months" to bring climate projections from six different global models down to the level of resolution needed to help New Zealand communities.

By the numbers

By 2090, the climate projections say New Zealand could:

• Be between 0.8°C and 3°C warmer, depending on how quickly emitters cut their greenhouse gases.
• Experience more days over 25°C and fewer frost days.
• Experience lower annual rainfall in the North Island, particularly in the north and the east, but higher annual rainfall in the west and south of the South Island.
• See more very rainy days (with more than 25 mm of rain) for many regions, especially in the west of the South Island.
• See increased drought exposure over the east of the North and South Islands

-RNZ