September is mixed in terms of weather in Sri Lanka with the best outcome likely to be early in the month. As you get into September, the approaching north-east monsoon begins to make itself noticed in many parts of the island, although most downpours tend to appear in the evening and days can still offer plenty of sunshine.
Sri Lanka's east coast is expecting its final month of good weather, so if it's beach time you're looking for then head to Pasikudah and Nilaveli. As October nears, however, the sense is of peak season gradually departing.
The Cultural Triangle remains hot, and more humid, and again the most intense downpours tend to be at night, coming as a relief as they bring life and freshness to the air. It is also a reasonable month to visit Colombo.
By September, it has been a long drought in the far south-east and Yala National Park is often closed at this time of year to allow animals to roam far and wide in search of ever scarcer water supplies.