April weather forecast
Kalutara, Sri Lanka

As we venture into April, there is a visible increasing trend in rainfall. The heat remains on a steady climb, with the highest temperature in April also topping at 31.3°C (88.3°F). This fluctuation leads to increased humidity, making the overall weather feel warmer than it is. Despite the increase in rainfall, April brings about pleasant weather dotted by tropical sunshine and longer daylight hours. The increasing rainfall during April indicates the onset of the monsoon season.

Temperature

Kalutara's warmest months, March and April, record an average high-temperature of 31.3°C (88.3°F).

Heat index

During April, the heat index is estimated at a blistering 41°C (105.8°F). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Be advised, the heat index considers values for conditions in shade and with a light breeze. 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 'apparent temperature', reflects the feeling of heat when considering both air temperature and humidity. One's perception of weather can be shaped by other factors, involving metabolic differences, pregnancy, and physical exertion. Given the impact of direct sunlight, it's noteworthy that the felt temperature can rise by 15 Fahrenheit (8 Celsius) degrees. Heat index values are primarily vital for children. Children often fail to recognize the requirement to rest and rehydrate. Thirst, being a late symptom of dehydration, underlines the importance of maintaining hydration, especially during ongoing physical activities.
When it comes to cooling down, the human body's primary method is through perspiration, making use of sweat evaporation to eliminate excess heat. Elevated relative humidity disrupts typical body cooling by reducing the evaporation rate, consequently decreasing the body's cooling rate and enhancing the feeling of heat. 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 April in Kalutara is 78%.

Rainfall

In Kalutara, during April, the rain falls for 25.8 days and regularly aggregates up to 127mm (5") of precipitation. Throughout the year, there are 273.8 rainfall days, and 2059mm (81.06") of precipitation is accumulated.

Sea temperature

April is the month with the warmest seawater in Kalutara, Sri Lanka, with an average sea temperature of 29.6°C (85.3°F).
Note: In any water activity, temperatures between 25°C (77°F) and 29°C (84.2°F) are viewed as magnificent and exceptionally pleasant for prolonged enjoyment.

Daylight

In April, the average length of the day is 12h and 16min.
On the first day of the month, sunrise is at 06:08 and sunset at 18:19. On the last day of April, sunrise is at 05:56 and sunset at 18:17 +0530.

Sunshine

In Kalutara, the average sunshine in April is 9h.

UV index

The months with the highest UV index in Kalutara are January through April, July, September through December, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high threat to health from unsafe exposure to UV radiation for ordinary individuals.
Note: The UV index of 7 during April translates into the following guidance:
Shun overexposure. Protection from sun ravages is indispensable. Be aware that the sun's UV radiation is strongest between 10 a.m. and 4 p.m. and try to reduce direct sun exposure during this period as much as possible. To cut down UV radiation exposure by about half, sport a wide-brim hat. Attention! UV strength is notably upped by the reflection of sand and water.