Sri Lanka weather in September
Sri Lanka averages 28°C by day and 25°C at night in September, with the sea at 29°C and 29 days with at least 1 mm of rain.
Day
28°C
Night
25°C
Sea
29°C
Rainy days
29
Flight from London
11h
What September feels like
September is hot but wet in Sri Lanka: rainy season, so pack for showers.
The sea is warm at 29°C: comfortable for long swims.
It is rainy season, with rain on about 29 days.
Of the 48 sun destinations we track, Sri Lanka is the #26 warmest in September.
Want it warmer in September?
These are hotter than Sri Lanka this month for at most an hour and a half more flying:
Sri Lanka weather by month
September is highlighted. Compare with August and October, or see the full year in Sri Lanka.
Sri Lanka in September: quick answers
Is Sri Lanka hot in September?
September is hot but wet in Sri Lanka: rainy season, so pack for showers. Average highs are 28°C and lows 25°C.
Can you swim in Sri Lanka in September?
The sea is warm at 29°C: comfortable for long swims.
Does it rain in Sri Lanka in September?
It is rainy season, with rain on about 29 days.
What is the warmest month in Sri Lanka?
March, at an average high of 31°C. The coolest is August at 28°C.
How long is the flight to Sri Lanka from the UK?
About 11h direct from London, estimated from the 8,838 km distance. Check your airline for exact times.
Still choosing? See where is hot in September for every destination ranked by temperature, sea and flight time.
How we measured this
Averages of every day in September from 2016 to 2025 for south coast, from the Open-Meteo historical weather archive (ECMWF ERA5 reanalysis). Sea temperature is the 2023 to 2025 average from the Open-Meteo marine archive. A rainy day has at least 1 mm of rain. Reanalysis describes an area about 25 km across, so sheltered resorts can run a degree or two warmer. Flight time is a distance-based estimate from London Heathrow.
Planning Sri Lanka in September?
Save the restaurants, beaches and views you find on TikTok and Instagram for Sri Lanka straight to a map, then let Dream Trip turn them into a day-by-day plan.
