December weather forecast
Chilaw, Sri Lanka

December, the first month of the winter in Chilaw, is also a moderately hot month, with an average temperature ranging between max 29.9°C (85.8°F) and min 23.7°C (74.7°F).

Temperature

Chilaw's weather in December displays an average high-temperature of a warm 29.9°C (85.8°F), showing minor disparity from November's 30.2°C (86.4°F). Chilaw's average low-temperature is measured at 23.7°C (74.7°F) during December.

Heat index

The heat index for December is appraised at a very hot 37°C (98.6°F). Ensure heightened precautions, risk of heat cramps and heat exhaustion is significant. Sustained activity could provoke heatstroke.
The metrics for the heat index are tailored for both shady environments and light winds. Heat index values may be hiked up by 15 Fahrenheit (8 Celsius) degrees under direct sunshine.
Note: The heat index, also known as 'real feel' or 'apparent temperature', gauges the sensation of temperature factoring in the air's moisture content. One's perception of weather can be shaped by other factors, involving metabolic differences, pregnancy, and physical exertion. Do note, being directly under sun rays can amplify the heat you feel, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely vital to babies and toddlers. Young children typically face greater hazards than adults because they do not sweat as much. Their larger skin surface in comparison to their little bodies and the high heat production from their active nature compounds their vulnerability.
The physiological way the human body responds to excessive heat is by inducing perspiration, using sweat evaporation as a cooling mechanism. Under high air temperature and humidity (high heat index) conditions, perspiration is limited, and the perception of heat is increased. Overheating dangers loom when the body's heat release mechanisms are overshadowed by excessive gain.

Humidity

The average relative humidity in December is 79%.

Rainfall

In Chilaw, in December, it is raining for 20.3 days, with typically 139mm (5.47") of accumulated precipitation. In Chilaw, during the entire year, the rain falls for 265.4 days and collects up to 1744mm (68.66") of precipitation.

Sea temperature

In Chilaw, in December, the average water temperature is 27.8°C (82°F).
Note: For water activities like swimming, diving, and more, temperatures ranging between 25°C (77°F) and 29°C (84.2°F) offer superior comfort and enjoyment for lengthy durations.

Daylight

December has the shortest days of the year, with an average of 11h and 42min of daylight.
On the first day of December, sunrise is at 06:08 and sunset at 17:51. On the last day of the month, sunrise is at 06:23 and sunset at 18:04 +0530.

Sunshine

In December, the average sunshine is 7h.

UV index

January through April, July, September, November and December, with an average maximum UV index of 7, are months with the highest UV index in Chilaw. A UV Index estimate of 6 to 7 represents a high threat to health from exposure to the Sun's UV rays for the ordinary person.
Note: In December, the average maximum UV index of 7 translates into the following recommendations:
Continue precautions and advocate sun safety advice. Deterrence of sunburn is indispensable. The Sun's UV radiation is most potent between the hours of 10 a.m. and 4 p.m. Try to avoid direct sunlight during this time. During bright days, sunglasses that offer UVA and UVB defense are recommended. Be on guard! The reflective nature of sand and water boosts UV exposure.