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 15 rainy, 8 partly cloudy, 4 cloudy, and 3 sunny days in April. The rains are usually heavy. April as well as March, May, June, and July is considered the most uncomfortable time to visit Invercargill.