September in Dundalk averages a daily high of 27.1°C with nights around 18.6°C. Expect roughly 8.8 wet days totalling 115.9mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Dundalk is April–May.
Based on MARYLAND SCIENCE CENTER, MD US (8.5km), 1995–2024. 24 years of September data.