Best time to visit Sri Lanka

• Mid December-mid March & July-September are the 2 great times to visit Sri Lanka
• These are the two dry seasons of the year in Sri Lanka so you get lots of sunshine
• September, in particular, is probably the single best month to visit because the number of tourists coming into the country is also relatively low so it's not as crowded as the other "dry" months
• Temperature wise, there's not too much month-to-month variation in Sri Lanka. The average temperature is 80-85 degrees (26-30 Celsius) throughout the year

Rainfall by month (source):

High (day time) and low (night time) temperature by month (source):

Tourist arrivals to Sri Lanka by month in 2017 (source):