January in Londonderry is the snowiest, the windiest, and the most freezing month of the year. In January, the weather in Londonderry is typically freezing. Average daily high temperature in January is about 1 degree below zero. On average, Londonderry has 13 partly cloudy, 12 sunny, 4 snowy, and 2 rainy days in January. The snowfalls are usually moderate.