May weather forecast
Colombo, Sri Lanka

May ushers in the wettest period in Colombo, with a staggering rainfall increase to 306mm (12.05"). The increase in cloud cover to 54% combined with a slight decrease in daylight hours could trigger a visually darker environment. Although the temperature during the day slightly decreases, evening temperatures continue to rise, resulting in very warm nights. May's weather creates an excellent opportunity for indoor activities and events, as outdoor adventures might be disrupted by the high rainfall and humidity. The relatively calm wind conditions might also be advantageous to those with outdoor plans.

Temperature

The transition into May shows a subtle variation to a still tropical 30.6°C (87.1°F) from April's 31.8°C (89.2°F) in the average high-temperature. May nights in Colombo, Sri Lanka, register a minor temperature decline, steadying at a warm 26.3°C (79.3°F).

Heat index

During May, the heat index is computed to be a blisteringly hot 40°C (104°F). Implement more safety precautions, heat cramps and heat exhaustion may happen. Persistent activity could induce heatstroke.
When referencing the heat index, its values are suitable for shady environments and light breezes. The heat index values could be amplified by up to 15 Fahrenheit (8 Celsius) degrees in direct sunlight.
Note: The heat index, also known as 'real feel' or 'felt air temperature', melds the effects of warmth and moisture to generate a feeling of heat. An individual's perception of weather can be affected by a variety of elements including metabolic differences, being pregnant, and their level of physical exertion. Direct sunlight exposure should be noted as it has the potential to increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Young people are generally more susceptible than adults because they perspire less. Furthermore, their proportionally larger skin surface to their petite bodies and the increased heat output from their actions add to the risk.
Perspiration and the resultant sweat evaporation are the body's natural thermostat, helping regulate temperature. When the air holds a significant amount of moisture, the efficiency of the evaporation process is decreased, preventing the body from cooling down efficiently, leading to the sensation of overheating. Accumulating more heat than the body can dissipate leads to an uptick in body temperature, with potential heat stress consequences.

Humidity

The average relative humidity in May in Colombo is 81%.

Rainfall

In Colombo, in May, during 28.8 rainfall days, 306mm (12.05") of precipitation is typically accumulated. Throughout the year, there are 289.4 rainfall days, and 2262mm (89.06") of precipitation is accumulated.

Sea temperature

In May, the average sea temperature in Colombo is 29.3°C (84.7°F).
Note: For swimming, diving, and other water activities, temperatures between 25°C (77°F) and 29°C (84.2°F) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

Daylight

The average length of the day in May in Colombo is 12h and 26min.
On the first day of the month, sunrise is at 05:56 and sunset at 18:18. On the last day of May, sunrise is at 05:53 and sunset at 18:23 +0530.

Sunshine

The average sunshine in May is 8.6h.

UV index

May, June, August and October, with an average maximum UV index of 6, are months with the lowest UV index in Colombo. A UV Index reading of 6 to 7 represents a high health vulnerability from exposure to the Sun's UV rays for the average person.
Note: The UV index of 6 during May translates into the following guidance:
Follow precautions and abide by sun safety rules. Deterrence of sunburn is imperative. From 10 a.m. to 4 p.m., when UV radiation is at its strongest, limit direct exposure to the Sun and note that shade structures may not provide full sun protection. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. Caution! The Sun's UV rays become stronger due to reflections from water and sand.