Climate averages 1991–2020
Colombo weather
by month.
See how the year changes. March has the highest average daily maximum; January has the lowest average monthly rainfall.
Long-term climate patterns, not a forecast for a particular trip.
Across the year Colombo averages a daytime high of 29.6°C and a nighttime low of 24.2°C, with about 2,243 mm of rain on roughly 249 days. March is the warmest month (average high 31.6°C) and August the coolest (28.4°C). October is the wettest month with 327 mm; January is the driest with 53 mm.
The annual picture
A year in Colombo
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Colombo climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 30.4°C22.9°C | 22.9°C | 53 | 7.8 | 11.812 h |
| February | 31.5°C23.4°C | 23.4°C | 55 | 7.8 | 11.912 h |
| March | 31.6°C24.4°C | 24.4°C | 75 | 14.9 | 12.112 h |
| April | 30.8°C25.0°C | 25.0°C | 167 | 24.8 | 12.312 h |
| May | 29.5°C25.4°C | 25.4°C | 279 | 28.9 | 12.412 h |
| June | 28.8°C25.1°C | 25.1°C | 242 | 26.7 | 12.513 h |
| July | 28.5°C24.8°C | 24.8°C | 183 | 24.4 | 12.512 h |
| August | 28.4°C24.6°C | 24.6°C | 168 | 23.6 | 12.312 h |
| September | 28.5°C24.5°C | 24.5°C | 223 | 24.5 | 12.212 h |
| October | 28.8°C24.1°C | 24.1°C | 327 | 26.0 | 12.012 h |
| November | 29.0°C23.6°C | 23.6°C | 307 | 23.7 | 11.812 h |
| December | 29.2°C23.2°C | 23.2°C | 164 | 15.6 | 11.712 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
Nearby cities
- Dehiwala-Mount LaviniaSri Lanka · 11 kmHigh 29.2°C · Low 24.3°C · 2,370 mm rain a year
- NegomboSri Lanka · 30 kmHigh 29.6°C · Low 24.6°C · 2,073 mm rain a year
- KandySri Lanka · 95 kmHigh 27.2°C · Low 20.7°C · 1,692 mm rain a year
- GalleSri Lanka · 107 kmHigh 28.3°C · Low 24.6°C · 2,171 mm rain a year
- MataraSri Lanka · 133 kmHigh 28.9°C · Low 24.5°C · 2,128 mm rain a year
- AmbalantotaSri Lanka · 158 kmHigh 30.6°C · Low 24.7°C · 1,137 mm rain a year
- BatticaloaSri Lanka · 221 kmHigh 31.2°C · Low 24.9°C · 1,286 mm rain a year
- KalmunaiSri Lanka · 225 kmHigh 30.4°C · Low 25.3°C · 1,397 mm rain a year
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsWhat do the high and low temperatures mean?
We average the daily maximum and daily minimum for each calendar month over 1991–2020. They are not record extremes, a forecast range or temperatures at a fixed time of day.
How is a rain day counted?
A local calendar day (standard time, UTC+5:30, no daylight saving) with at least 1 mm of total precipitation counts as one rain day. We count these for each year and month, then average across 30 years. The average does not predict which days will be wet.
Where do the numbers come from?
ERA5-Land (temperature) and ERA5 (precipitation) reanalysis from the Copernicus Climate Change Service, read from the Open-Meteo open-data archive. Temperature comes from the 0.1° model cell at 6.90°, 79.90° (7 km from the city centre). Rain comes from the 0.25° cell at 7.00°, 79.75°. These are model estimates, not weather-station readings; coast, hills and city streets can differ.
Does this page show sunshine, humidity or sea temperature?
No. The data used here contain air temperature and precipitation only. Daylight hours are calculated from the city's latitude (sunrise to sunset), not measured sunshine.