New Zealand extends from 34° s to 47° s and thus lies within the broad belt of westerly winds which encircles the hemisphere in the temperate latitudes. Situated in the midst of a vast ocean and far removed from the nearest large land masses, it enjoys a climate that is essentially maritime-temperate, characterised by rapid weather changes, frequent though not excessive rain, and a small range of temperature from winter to summer. Combined with an abundance of sunshine, these conditions are very favourable for a wide variety of plants, particularly for high-grade pasture grasses so important to the meat, wool, and dairy industries which produce the bulk of the country's wealth.

Within New Zealand the climate shows considerable variation, due chiefly to the shape and topography of the country itself. The chain of high mountains extending from south-west to north-east for 800 miles rises as a formidable barrier in the path of the prevailing westerly winds. The effect is to produce much sharper climatic contrasts from west to east than in the north-south direction. In some inland areas of the South Island just east of the mountains the climate is distinctly continental in character, despite the fact that no part of New Zealand is more than 90 miles from sea.