April weather forecast
Colombo, Sri Lanka

In April, Colombo experiences the first major surge of rainfall in the year, shooting up to 137mm (5.39") over 25.4 days. This increase coincides with the highest temperature peaks of 31.8°C (89.2°F), resulting in particularly humid and hot conditions. A slightly expanded daylight period allows for ample sightseeing time, despite the frequent rain showers. Moreover, the sea experiences a warming trend, perfect for swimmers and divers. However, the cloudy conditions, coupled with increased rainfall, may affect outdoor plans.

Temperature

Colombo sees its peak of temperatures during March and April, with an average high-temperature of 31.8°C (89.2°F).

Heat index

The heat index in April is computed to be a blisteringly hot 42°C (107.6°F). More preventive actions are needed, risk of heat exhaustion and heat cramps is significant. Prolonged activity may trigger heatstroke.
In the scope of the heat index, its values resonate with shade and light wind conditions. In the presence of direct sunshine, the heat index could be augmented by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'feels like', marries air temperature and humidity to produce a value illustrating perceived warmth. The effect of weather is individual, with a variety of people experiencing it differently due to distinctions in body mass, height, and level of activity. Be mindful that being in direct sunlight might mean feeling hotter, with the heat index rising by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young individuals are generally in more danger than adults due to their lower capacity to sweat. Moreover, their large skin surface in relation to their small bodies and the increased heat generation from their activities makes them more vulnerable.
The innate cooling system of the human body revolves around perspiration, with the evaporation of sweat being central to this process. With excessive moisture in the atmosphere, the effectiveness of the evaporation process is decreased, causing the body to cool down less efficiently, leading to a sensation of overheating. Overheating risks increase with rising body temperatures, especially if heat release isn't efficient.

Humidity

In Colombo, the average relative humidity in April is 77%.

Rainfall

In Colombo, Sri Lanka, during April, the rain falls for 25.4 days and regularly aggregates up to 137mm (5.39") of precipitation. In Colombo, during the entire year, the rain falls for 289.4 days and collects up to 2262mm (89.06") of precipitation.

Sea temperature

With an average sea temperature of 29.6°C (85.3°F), April is the month with the warmest seawater.
Note: Swimming, diving, and other water-related activities in temperatures between 25°C (77°F) and 29°C (84.2°F) are considered highly enjoyable and satisfying for longer durations without uneasiness.

Daylight

The average length of the day in April in Colombo, Sri Lanka, is 12h and 17min.
On the first day of the month, sunrise is at 06:08 and sunset at 18:20. On the last day of April, in Colombo, sunrise is at 05:56 and sunset at 18:18 +0530.

Sunshine

The average sunshine in April in Colombo is 8.9h.

UV index

The months with the highest UV index in Colombo are January through April, July, September, November and December, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health risk from exposure to the Sun's UV radiation for ordinary individuals.
Note: The maximum UV index of 7 during April translates into these guidelines:
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-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage. Be on guard! The reflective nature of sand and water boosts UV exposure.