April in Istra-1 is the rainiest month of the year. In April, the weather in Istra-1 is typically cold. Average daily high temperature in April is about 9 degrees above zero. On average, Istra-1 has 18 rainy, 6 cloudy, 5 sunny, and 1 partly cloudy day in April. The rains are usually moderate. April as well as March, May, October, and November is considered the most uncomfortable time to visit Istra-1.