January in Monaghan is the coldest month of the year. In January, the weather in Monaghan is typically cold. Average daily high temperature in January is about 7 degrees above zero. On average, Monaghan has 14 rainy, 10 partly cloudy, 5 cloudy, and 2 sunny days in January. The rains are usually heavy. January as well as February, March, April, and May is considered the most uncomfortable time to visit Monaghan.