In April, the weather in Invercargill is typically warm. Average daily high temperature in April is about 14 degrees above zero. On average, Invercargill has 20 rainy, 5 cloudy, 4 sunny, and 1 partly cloudy day in April. The rains are usually heavy. April as well as January, March, May, and June is considered the most uncomfortable time to visit Invercargill.