Colombo Weather in September

Colombo in September sees very high daytime temperatures of 30°C (86°F) and nighttime lows of 25°C (77°F). As part of the rainy season, showers are frequent and often heavy. Budget around 262 mm (10 in) of rainfall for the month.

Rainfall in Colombo in September

As part of the rainy season, Colombo sees around 14 days of rain in September, with an average of 262 mm (10 in). With high rainfall totals spread across the month, individual showers can be very heavy. Waterproof gear is strongly recommended.

Temperature in Colombo in September

Daytime temperatures in Colombo reach 30°C (86°F) in September, dropping to 25°C (77°F) at night. Indoor breaks or shaded spots can make the warmer part of the day much more comfortable. With overnight lows of 25°C (77°F), evenings and nights remain warm. Light clothing and an open window or fan can help you sleep comfortably.

Sunshine in Colombo in September

You can expect a moderate amount of sunlight, with approximately 189 hours. Even though this month is part of the wet season, you can still see the sun occasionally.

Wind Speed in Colombo in September

Wind speeds average 2 m/s (4 knots) during September. At this speed, expect light breezes that you can feel on your face and cause leaves to rustle gently. Since this is an average, some days are calmer with barely any wind while others have more noticeable gentle breezes.

Average water temperature in September

The water temperature is 28°C (82°F), which most people find very comfortable. A good month for swimming and water sports.

September in Colombo can still be great, but if you prefer pleasant temperatures along with dry and sunny conditions, our weather planner can help you explore other options in the world.

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For a detailed overview over the year and the best time to visit Sri Lanka, check out our Colombo's climate page.

Colombo Temperature in September

Min Temperature 25°C (77°F)  

Max Temperature 30°C (86°F)  

Water Temperature 28°C (82°F)  

Chance of Rain 45%  

Precipitation 262 mm (10 in)  

Rainy days 14 days  

Humidity 76%  

Windspeed 2 m/s (4 knots)  

Sunshine 189 hours  

Percentage Sunshine  

Daily Historical Temperatures

46-year average (1976-2025)

Based on our historical records, temperatures in Colombo typically stay consistent throughout September, with daily highs averaging around 30°C (86°F). Nights are warm, with lows around 26°C (79°F).

Average temperatures in September

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Daily Historical Precipitation

46-year average (1976-2025)

Average daily rainfall for each day of the month based on long-term records.

Average precipitation in September

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Historical weather for Colombo in September

Browse day-by-day weather records for Colombo spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.

Historical weather Temperatures Precipitation

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‹ January February March April May June July August September October November December ›

Colombo historical weather extremes in September

According to our 27 years of weather records for Colombo, the following extremes were recorded between 1998 and 2025.

• The warmest day in September was on September 18, 2019, with a maximum of 34°C (93°F).
• On September 24, 2000, Colombo saw its coldest September day with temperatures maxing out at 25°C (77°F).
• The lowest overnight temperature recorded in September was 22°C (72°F) (September 9, 2007).

What to Wear in Colombo in September

Warm temperatures in September make for comfortable sightseeing weather. Pack breathable fabrics like cotton shirts, knee-length shorts or skirts, and comfortable walking shoes. A thin long sleeve for indoor spaces is handy. Heavy rain is guaranteed, please bring a good poncho and waterproof everything! With water temperatures around 28°C (82°F), swimming conditions are excellent. Pack your swimsuit, goggles, and maybe some water shoes. Bring sunglasses since you'll have some sunny periods throughout the month

What To Do in Colombo in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

7/10

Cycling

7/10

Walking

7/10

Camping

7/10

Outdoor sports

7/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit Sri Lanka, check out our Colombo's climate page.

More climate data for Colombo

Temperature Rainfall Sunshine Humidity Wind Speed Water Temp

See the full Colombo climate overview or explore weather in Sri Lanka.