Why are the Canterbury Plains different from the west coast of South Island?

The Canterbury Plains and the West Coast of the South Island are distinct primarily due to the Southern Alps, which act as a major climatic and physical barrier.123

• Climatic Contrast: The Southern Alps intercept prevailing westerly winds, causing heavy orographic precipitation on the windward West Coast. Conversely, the Canterbury Plains lie in the rain shadow on the leeward side, resulting in a much drier climate with a mean annual rainfall of less than 30 inches. The region also experiences the foehn effect, a warm, dry wind that further lowers humidity.245
• Landscape and Land Use: The West Coast is characterized by rugged, mountainous terrain, glaciers, and dense forests, with an economy historically tied to mining and timber. In contrast, the Canterbury Plains form a vast, low-lying area well-suited for mechanized, intensive agriculture, including grain production and sheep farming.153