In May, the weather in Llangefni is typically warm. Average daily high temperature in May is about 13 degrees above zero. On average, Llangefni has 17 rainy, 7 sunny, 5 partly cloudy, and 2 cloudy days in May. The rains are usually moderate. May as well as January, February, March, and July is considered the most uncomfortable time to visit Llangefni.