December weather forecast and climate
Colombo, Sri Lanka

Statues on the Seema Malaka Temple in Colombo, Sri Lanka, overlooking the Beira Lake
Statues on the Seema Malaka Temple in Colombo, Sri Lanka, overlooking the Beira Lake

Weather in December

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

Temperature

In Colombo, Sri Lanka, the average high-temperature in December is relatively the same as in November - a warm 29.9°C (85.8°F). The average low-temperature, in December, is 23.7°C (74.7°F).

Heat index

The average heat index in December is calculated to be a torrid 37.1°C (98.8°F). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Note that heat index values are valued for light wind and location in the shade. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'real feel', 'felt air temperature', or 'feels like', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. Additional factors like activity, metabolic differences, clothing, and pregnancy 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 particularly important for children. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
The human body normally cools itself by perspiration, as evaporated sweat carries heat away from the body. Under high air temperature and humidity (high heat index) conditions, perspiration is limited, and the perception of heat is increased. When heat gain exceeds the level the body can remove, body temperature begins to rise, and heat-related illnesses and disorders may develop.

Humidity

In December, the average relative humidity in Colombo is 79%.

Rainfall

In December, in Colombo, the rain falls for 21.1 days. Throughout December, 148mm (5.83") of precipitation is accumulated. Throughout the year, there are 289.4 rainfall days, and 2262mm (89.06") of precipitation is accumulated.

Sea temperature

In December, the average sea temperature is 28.1°C (82.6°F).
Note: For any water activity, surface water temperatures between 25°C (77°F) and 29°C (84.2°F) are considered as excellent and extremely pleasant for lengthened periods.

Daylight

With an average of 11.7h of daylight, December has the shortest days of the year in Colombo.

Sunshine

In December, the average sunshine in Colombo, Sri Lanka, is 6.9h.

UV index

Months with the highest UV index 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 hazard from the exposure to the Sun's UV rays for average individuals.
Note: The average daily UV index of 7 transform into the following instructions:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Caution! The reflection of sand and water significantly increases the intensity of the Sun's UV radiation.
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FAQ

What is the temperature in December in Colombo?

In December, the average high-temperature is 29.9°C (85.8°F), and the average low-temperature is 23.7°C (74.7°F). The average heat index (a.k.a. 'feels like', 'felt air temperature'), which combines relative humidity and air temperature, in December is calculated to be 37.1°C (98.8°F).

What is the average humidity in December in Colombo?

In Colombo, the average relative humidity in December is 79%.

How many days does it rain in December in Colombo?

In Colombo, Sri Lanka, in December, it is raining for 21.1 days, with typically 148mm (5.83") of accumulated precipitation.

What is the water temperature in December in Colombo?

In December, the average sea temperature in Colombo is 28.1°C (82.6°F). 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.

What is the month with the shortest days in Colombo?

December has the shortest days of the year in Colombo, Sri Lanka, with an average of 11.7h of daylight.

How many hours of daylight does Colombo have in December?

In Colombo, the average length of the day in December is 11.7h.

How long on average sun shines in December in Colombo?

The average sunshine in December in Colombo, Sri Lanka, is 6.9h.

When is the highest UV index in Colombo?

January through April, July, September, November and December, with an average maximum UV index of 7, are months with the highest UV index in Colombo.

What is the UV index intensity in December in Colombo?

In Colombo, Sri Lanka, the average daily maximum UV index in December is 7. A UV Index of 6 to 7 symbolizes a high hazard to health from the exposure to the Sun's UV rays.

Average temperature in December
Colombo, Sri Lanka

Average temperature in December - Colombo, Sri Lanka
  • Average high temperature in December: 29.9°C

The warmest months (with the highest average high temperature) are March and April (31.8°C).
Months with the lowest average high temperature are July and August (28.9°C).

  • Average low temperature in December: 23.7°C

The month with the highest average low temperature is May (26.3°C).
The coldest month (with the lowest average low temperature) is January (23.1°C).

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Average pressure in December
Colombo, Sri Lanka

Average pressure in December - Colombo, Sri Lanka
  • Average pressure in December: 1010.4mbar

The month with the highest atmospheric pressure is January (1011.6mbar).
The month with the lowest atmospheric pressure is May (1008.6mbar).

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Average wind speed in December
Colombo, Sri Lanka

Average wind speed in December - Colombo, Sri Lanka
  • Average wind speed in December: 11.5km/h

The windiest month (with the highest average wind speed) is June (15.1km/h).
The calmest month (with the lowest average wind speed) is March (8km/h).

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Average humidity in December
Colombo, Sri Lanka

Average humidity in December - Colombo, Sri Lanka
  • Average humidity in December: 79%

Months with the highest relative humidity are June, July and August (83%).
Months with the lowest relative humidity are January and February (74%).

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Average rainfall in December
Colombo, Sri Lanka

Average rainfall in December - Colombo, Sri Lanka
  • Average rainfall in December: 148mm

The wettest month (with the highest rainfall) is June (341mm).
The driest month (with the least rainfall) is January (40mm).

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Average rainfall days in December
Colombo, Sri Lanka

Average rainfall days in December - Colombo, Sri Lanka
  • Average rainfall days in December: 21.1 days

The month with the highest number of rainy days is August (30.2 days).
The month with the least rainy days is January (11.6 days).

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Average sea temperature in December
Colombo, Sri Lanka

Average sea temperature in December - Colombo, Sri Lanka
  • Average sea temperature in December: 28.1°C

The best month for swimming (with the highest average sea temperature) is April (29.6°C).
The coldest month (with the lowest average sea temperature) is August (27.2°C).

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Average daylight in December /
Average sunshine in December
Colombo, Sri Lanka

Average daylight in December / Average sunshine in December - Colombo, Sri Lanka
  • Average daylight in December: 11.7h

Months with the longest days are June and July (Average daylight: 12.5h).
The month with the shortest days is December (Average daylight: 11.7h).

  • Average sunshine in December: 6.9h

The month with the most sunshine is January (Average sunshine: 9.1h).
The month with the least sunshine is November (Average sunshine: 6.7h).

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Average sunshine days in December
Colombo, Sri Lanka

Average sunshine days in December - Colombo, Sri Lanka
  • Average sunshine days in December: 8.3 days

The month with the most sunshine days is January (17.2 days).
Months with the least sunshine days are June and August (0.3 days).

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Average UV index in December
Colombo, Sri Lanka

Average UV index in December - Colombo, Sri Lanka
  • Average UV index in December: 7

Months with the highest UV index are January, February, March, April, July, September, November and December (UV index 7).
Months with the lowest UV index are May, June, August and October (UV index 6).

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Average cloud cover in December
Colombo, Sri Lanka

Average cloud cover in December - Colombo, Sri Lanka
  • Average cloud cover in December: 38

The month with the most cloud cover is June (Cloud cover 57).
The month with the least cloud cover is January (Cloud cover 24).

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Average visibility in December
Colombo, Sri Lanka

Average visibility in December - Colombo, Sri Lanka
  • Average visibility in December: 10km

Months with the highest visibility are January, February, March, April and December (10km).
Months with the lowest visibility are May, June, July, August, September, October and November (9km).

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