December in Negombo averages a daily high of 30.9°C with nights around 23.9°C. Expect roughly 13.8 wet days totalling 252.6mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Negombo is January–February.
Based on COLOMBO, CE (34.5km), 1995–2024. 13 years of December data.