In May, the weather in Carrick-on-Shannon is typically warm. Average daily high temperature in May is about 13 degrees above zero. On average, Carrick-on-Shannon has 24 rainy, 4 sunny, 2 cloudy, and 1 partly cloudy day in May. The rains are usually heavy. May as well as January, February, March, and April is considered the most uncomfortable time to visit Carrick-on-Shannon.