December weather forecast
Vavuniya, Sri Lanka

The advent of December in Vavuniya signifies the onset of winter, albeit a tropical one. With the lowering evening temperature settling around 21.7°C (71.1°F), the slight chill in the air confirms winter’s arrival. The month witnesses the retreat of the rainfall with a considerable decrease down to 107mm (4.21"), marking a clear transition into a drier part of the year. Winter solstice towards the end of the month also means that daylight duration shrinks a tad. However, the increase in cloud cover combined with cooler conditions makes December arguably the most pleasant month weather-wise in Vavuniya.

Temperature

December, recording an average high temperature of 29.5°C (85.1°F) and a low temperature of 21.7°C (71.1°F), is Vavuniya's coldest month.

Heat index

The heat index value during December is estimated at a torrid 37°C (98.6°F). Take greater precautions, heat exhaustion and heat cramps may be expected. Heatstroke could result from lengthy activity.
Be advised, the heat index considers values for conditions in shade and with a light breeze. Being exposed to direct sunshine might trigger a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', represents the fusion of temperature and moisture in the air to suggest how warm it feels. An individual's perception of weather can be swayed by a variety of elements including metabolic differences, pregnancy status, and their level of physical exertion. One's exposure to direct sunlight has the potential to intensify the heat sensation, increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Young individuals usually face more risks than adults due to their lower sweat production. Their large skin surface area relative to their tiny bodies and high heat production from their activities adds to their risk.
Perspiration and the resultant sweat evaporation are the body's natural thermostat, helping regulate temperature. An upsurge in relative humidity affects normal body cooling mechanisms by slowing evaporation, hence reducing the rate at which the body cools and intensifying the perception of heat. As body temperatures escalate without effective heat release, one might face dehydration threats.

Humidity

With an average relative humidity of 84%, December is the most humid month in Vavuniya.

Rainfall

In Vavuniya, during December, the rain falls for 22.4 days and regularly aggregates up to 107mm (4.21") of precipitation. Throughout the year, there are 199.1 rainfall days, and 893mm (35.16") of precipitation is accumulated.

Daylight

With an average of 11h and 36min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 06:07 and sunset at 17:46. On the last day of December, in Vavuniya, sunrise is at 06:22 and sunset at 17:59 +0530.

Sunshine

With an average of 5.1h of sunshine, December has the least sunshine of the year in Vavuniya.

UV index

The months with the lowest UV index in Vavuniya are January, October through December, with an average maximum UV index of 6. A UV Index value of 6 to 7 symbolizes a high threat to health from unprotected exposure to Sun's UV rays for the ordinary person.
Note: A maximum UV index of 6 in December translates into the following recommendations:
Embrace precautions and observe sun safety norms. Evasion of sunburn is a necessity. To the best of your ability, limit your exposure to the sun between the hours of 10 a.m. and 4 p.m., when UV radiation is at its peak. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.