January in Dublin is the windiest and the coldest month of the year. In January, the weather in Dublin is typically cold. Average daily high temperature in January is about 6 degrees above zero. On average, Dublin has 16 rainy, 10 cloudy, 4 sunny, and 1 partly cloudy day in January. The rains are usually moderate. January as well as February, March, April, and May is considered the most uncomfortable time to visit Dublin.