January in Longueuil averages a daily high of -4°C with nights around -11.4°C. Expect roughly 14.6 wet days totalling 80.4mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Longueuil is May–September.
Based on MCTAVISH, QC CA (9.1km), 1995–2024. 29 years of January data.