In April, the weather in Norrtalje is typically cold. Average daily high temperature in April is about 9 degrees above zero. On average, Norrtalje has 10 partly cloudy, 8 sunny, 7 rainy, and 5 cloudy days in April. The rains are usually light. April as well as January, February, March, and May is considered the most uncomfortable time to visit Norrtalje.