April in Kailua-Kona is the rainiest month of the year. In April, the weather in Kailua-Kona is typically warm. Average daily high temperature in April is about 23 degrees above zero. On average, Kailua-Kona has 12 partly cloudy, 10 cloudy, 5 rainy, and 3 sunny days in April. The rains are usually light.