December in Dundalk averages a daily high of 8.8°C with nights around 1.9°C. Expect roughly 10.3 wet days totalling 98.3mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Dundalk is April–May.
Based on MARYLAND SCIENCE CENTER, MD US (8.5km), 1995–2024. 23 years of December data.