When the humid westerly airstreams from the Tasman Sea reach the West Coast, they rise over the mountains and cool. Water vapour condenses as rain, which drops on the coast and the Southern Alps. Once over the mountains, the air descends and warms up, and the moisture evaporates. The winds then cross to Canterbury, on the east coast, bringing much drier weather.
Using this item
This item has been provided for private study purposes (such as school projects, family and local history research) and any published reproduction (print or electronic) may infringe copyright law. It is the responsibility of the user of any material to obtain clearance from the copyright holder.