Colombo weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Fair
Best time to visit: January – February
What is the weather like in Colombo in September?
In September, Colombo is hot: daytime highs average 29 °C, and even at night it stays warm at around 25 °C. The sea averages 27.9 °C – lovely and warm for swimming. Expect around 6 hours of sunshine a day. It is the rainy season: rain falls on about 28 days, totalling 257 mm. The air is often humid and muggy. All in all, September is a so-so month for a holiday in Colombo.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 51 | 49 | 46 |
| Day | 29° | 29° | 29° |
| Night | 25° | 25° | 24° |
| Sea | 28° | 28° | 28° |
| Sun | 6 h | 6 h | 5 h |
| Rain days | 29 | 28 | 28 |
More details for September
- Daylight
- 12 h 10 min06:01 – 18:11
- UV index
- 14 · extremeclear sky, noon (estimate)
- Muggy days
- 30 daysdew point 18 °C or more
- Wind
- 16 km/haverage daily peak
- Cloud cover
- 84 %on average
- Hot days
- 1 day30 °C or more
- Time zone
- UTC+5:30Asia/Colombo
How the score comes together
- Temperatureweight 50 %80 %
- Sunshineweight 20 %43 %
- Few rainy daysweight 30 %0 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Swimwear
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
- Insect repellent
- Rain jacket or umbrella
Colombo in September: quick answers
Is Colombo hot in September?
Yes. In September, Colombo is hot: daytime highs average 29 °C and nights stay around 25 °C.
Can you swim in Colombo in September?
Yes. In September the sea averages 27.9 °C – lovely and warm for swimming.
Does it rain much in Colombo in September?
It rains often – on about 28 days, adding up to 257 mm.
Colombo month by month
The whole year in ColomboAll destinations: Sri Lanka
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, GeoNames (CC BY 4.0)