The coldest month is usually July and the warmest month is usually January or February. In New Zealand generally there are relatively small variations between summer and winter temperatures, although inland and to the east of the ranges the variation is greater (up to 14°C).

July is statistically the coldest month on the South Island of New Zealand. During this mid-winter period, the inland alpine regions near the Southern Alps experience frequent sub-zero temperatures, often dropping to -5°C to -10°C (14°F to 23°F) at night in towns like Queenstown, Wanaka, and Tekapo. While coastal cities like Christchurch and Dunedin are slightly milder due to maritime influences, they still face biting southerly winds and average daytime highs of only 8°C to 11°C (46°F to 52°F). July is the peak month for the ski season, with the most consistent snowpack on the mountains, but it also brings the shortest daylight hours of the year. Travelers visiting in July should be prepared for "black ice" on the roads, especially when driving over mountain passes like the Lindis Pass or Arthur's Pass. Despite the cold, July offers some of the most spectacular "crisp" blue-sky days, making it a favorite for photographers wanting to capture the snow-capped peaks against the turquoise lakes of the Mackenzie Country.