Climate averages 1991–2020
Colombo weather
in May.
A hot, very wet month: the 5th warmest and the 10th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a hot month in Colombo: daytime highs average 29.5°C and nights cool to about 25.4°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 279 mm of rain on roughly 29 days, which makes May a very wet month (the 10th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 26 min on an average May day.
The nearest other city in this atlas is Dehiwala-Mount Lavinia (11 km away). In May its highs average 29.2°C, about as warm as Colombo, with 293 mm of rain.
Among the 12 cities listed in Sri Lanka, Colombo ranks 8th of 12 for the warmest May highs and joint 10th of 12 for the driest May (rainfall, lowest first). The mean May high of those 12 cities is 30.6°C; Colombo is 1.1°C cooler than that mean.
From May to June, average highs fall by 0.7°C to 28.8°C, and monthly rainfall falls from 279 mm to 242 mm.
The annual picture
May in context
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, selected | 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
May in nearby cities
- Dehiwala-Mount Lavinia in MaySri Lanka · 11 kmHigh 29.2°C · Low 25.4°C · 293 mm rain
- Negombo in MaySri Lanka · 30 kmHigh 29.6°C · Low 25.7°C · 255 mm rain
- Kandy in MaySri Lanka · 95 kmHigh 28.0°C · Low 22.0°C · 125 mm rain
- Galle in MaySri Lanka · 107 kmHigh 28.6°C · Low 25.5°C · 279 mm rain
- Matara in MaySri Lanka · 133 kmHigh 29.0°C · Low 25.4°C · 224 mm rain
- Ambalantota in MaySri Lanka · 158 kmHigh 31.0°C · Low 25.9°C · 101 mm rain
- Batticaloa in MaySri Lanka · 221 kmHigh 33.4°C · Low 26.2°C · 50 mm rain
- Kalmunai in MaySri Lanka · 225 kmHigh 32.3°C · Low 26.6°C · 59 mm rain
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 limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Colombo) is explained once on the Colombo year overview and on the Sources, method and limits page.