December in Amarillo averages a daily high of 11.2°C with nights around -3.5°C. Expect roughly 3.7 wet days totalling 16.1mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Amarillo is March–May.
Based on AMARILLO AIRPORT, TX US (11.2km), 1995–2024. 30 years of December data.