December in Port Arthur averages a daily high of 18.7°C with nights around 7.8°C. Expect roughly 9.2 wet days totalling 117.3mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Port Arthur is February–April.
Based on PORT ARTHUR SE TX REGIONAL AIRPORT, TX US (11km), 1995–2024. 30 years of December data.