The climate of this area is greatly dependent on its exposure to weather systems from the Tasman Sea and the lie of the Southern Alps to the east.

The Standardised Precipitation Index (SPI) is a simple measure of drought (and also of very wet conditions) and is based solely on the accumulated precipitation for a given time period.

If you list all the historic rainfall totals for a particular month and for a specific location, rank these from lowest to highest, then divide the list into ten equal parts, you have identified the ten rainfall deciles for that month and for that location.

Reports produced by NIWA’s air quality research.

Common questions about clouds, how they are formed and how they behave.

Northland, with its northern location, low elevation and close proximity to the sea is characterised by a mild, humid, and rather windy climate.

This web camera is available thanks to the support of Waikato Regional Council.

NIWA maintains the national climate database for New Zealand, and can supply data in a variety of ways.

The Intergovernmental Panel on Climate Change (IPCC) is charged with assessing the most up to date scientific, technical and socio-economic research on climate change.

New Zealand has low-lying coastal areas that are vulnerable to inundation (flooding) by the sea.

How may agricultural activities increase sediments in waterways?