January in London averages a daily high of -1.5°C with nights around -8.7°C. Expect roughly 17.5 wet days totalling 72.1mm. A hard month to visit for comfort alone.
Across the year, the best time to visit London is May–September.
Based on LONDON CS, ON CA (8.7km), 1995–2024. 22 years of January data.