May weather forecast
Colombo, Sri Lanka

May, the last month of the spring in Colombo, is another hot month, with an average temperature ranging between min 26.3°C (79.3°F) and max 30.6°C (87.1°F).

Temperature

In Colombo, the average high-temperature in May is practically the same as in April - a still hot 30.6°C (87.1°F). The average low-temperature, is 26.3°C (79.3°F).

Heat index

The average heat index in May is estimated at a scorching 40°C (104°F). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like', 'felt air temperature', 'apparent temperature', or 'real feel', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. Additional factors like activity, differences in body mass, height, and shape, wind, and clothing affect individual temperature impact. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.
The human body cools itself through perspiration, as excessive warmth is removed from the body through sweat evaporation. With a lot of moisture in the air, the evaporation process is not as effective, and the body does not cool down as efficiently, creating a perception of overheating. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

In May, the average relative humidity is 81%.

Rainfall

In Colombo, 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 Colombo, the average seawater temperature in May 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 May, sunrise is at 05:56 and sunset at 18:18. On the last day of the month, sunrise is at 05:53 and sunset at 18:23 +0530.

Sunshine

In Colombo, 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 value of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV radiation for the average person.
Note: The average daily UV index of 6 in May transform into the following instructions:
Take precautions and utilize sun safety practices. Protection against skin and eye damage is required. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.