Eastern South Island

The climate of this zone is greatly dependent on the lie of the massive Southern Alps to the west. Summer temperatures are warm, with highest temperatures occurring when hot dry foehn northwesterlies blow over the Alps and plains. Mean annual rainfall is low, and long dry spells can occur, especially in summer. For much of the time summer temperatures are moderated by a cool northeasterly sea breeze.

Typical summer daytime maximum air temperatures range from 18°C to 26°C, but may rise to more than 30°C. A temperature of 42°C has been recorded in Christchurch. Winters are cold with frequent frost. Typical winter daytime maximum air temperatures range from 7°C to 14°C. Northeasterlies prevail about the coast for much of the year. Southwesterlies are more frequent during winter.

Western South Island

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. Although mean annual rainfall is very high, dry spells do occur, especially in late summer and during winter. Heavy rainfall occurs from the northwest. Summers are mild.

Typical summer daytime maximum air temperatures range from 17°C to 22°C and seldom exceed 25°C. Winter days often start with frost. Typical winter daytime maximum air temperatures range from 10°C to 14°C. Northnortheast winds prevail along the coast in Westport and Hokitika while southwesterlies prevail in coastal areas further south. Sea breezes can occur on warm summer days.