January in London is the coldest month of the year. In January, the weather in London is typically cold. Average daily high temperature in January is about 6 degrees above zero. On average, London has 16 rainy, 9 cloudy, 5 sunny, and 1 partly cloudy day in January. The rains are usually moderate. January as well as February, March, June, and November is considered the most uncomfortable time to visit London.