June in Castlebar is the cloudiest month of the year. In June, the weather in Castlebar is typically warm. Average daily high temperature in June is about 15 degrees above zero. On average, Castlebar has 25 rainy, 2 sunny, 2 cloudy, and 1 partly cloudy day in June. The rains are usually heavy. June as well as January, February, March, and April is considered the most uncomfortable time to visit Castlebar.