December weather forecast
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 an average temperature ranging between min 23.7°C (74.7°F) and max 29.9°C (85.8°F).

Temperature

In Colombo, Sri Lanka, the average high-temperature in December is practically the same as in November - a moderately hot 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 estimated at a sweltering 37°C (98.6°F). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Take into consideration that the heat index values are calculated for shade and light wind conditions. With exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature', 'apparent temperature', 'real feel', or 'feels like', is a measure that combines air temperature and relative humidity into a single value that indicates how hot the weather feels. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (pregnancy, differences in body mass, height, and shape, clothing). 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 especially crucial for babies and toddlers. 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. Excessive warmth is eliminated from the body by evaporation of sweat. When the relative humidity is high, the evaporation rate is reduced. The warmth is removed from the body at a lower rate, causing the body to retain more heat than it would in dry air. If the body can not disperse the excessive heat and body temperature reaches conditions of hyperthermia, above 37.5°C (99.5°F) to 38.3°C (100.9°F), thermal conditions are potentially life-threatening.

Humidity

The average relative humidity in December in Colombo is 79%.

Rainfall

In December, the rain falls for 21.1 days. Throughout December, 148mm (5.83") of precipitation is accumulated. In Colombo, during the entire year, the rain falls for 289.4 days and collects up to 2262mm (89.06") of precipitation.

Sea temperature

In Colombo, the average water temperature is 28.1°C (82.6°F).
Note: 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.

Daylight

With an average of 11h and 44min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 06:06 and sunset at 17:51. On the last day of December, in Colombo, sunrise is at 06:21 and sunset at 18:05 +0530.

Sunshine

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

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. A UV Index estimate of 6 to 7 represents a high health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: The average daily UV index of 7 in December transform into the following instructions:
Take precautions against overexposure. Fair-skinned people may get burned in less than 20 minutes. 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. 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, in Colombo, Sri Lanka, the average high-temperature is 29.9°C (85.8°F), and the average low-temperature is 23.7°C (74.7°F). in December, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which takes the relative humidity and factors it into the air temperature reading, is estimated at 37°C (98.6°F).

What is the average humidity in December in Colombo?

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

How much does it rain in Colombo in December?

In Colombo, in December, during 21.1 rainfall days, 148mm (5.83") of precipitation is typically accumulated.

What is the sea water temperature in December in Colombo?

In December, the average sea temperature 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?

With an average of 11h and 44min of daylight, December has the shortest days of the year.

How many hours of daylight does Colombo have in December?

In Colombo, Sri Lanka, the average day length in December is 11h and 44min.

When is the sunrise / sunset in December in Colombo?

In December, on the first day of the month, sunrise is at 06:06 and sunset at 17:51. On the last day of the month, sunrise is at 06:21 and sunset at 18:05 +0530.

How long on average sun shines in December in Colombo?

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

What are the months with 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 reading in December in Colombo?

In December, the average daily maximum UV index in Colombo is 7. A UV Index estimate of 6 to 7 represents a high health vulnerability from unsafe exposure to 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).
The 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%

The months with the highest relative humidity are June, July and August (83%).
The 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: 11h and 4min

The month with the longest days is June (Average daylight: 12h and 30min).
The month with the shortest days is December (Average daylight: 11h and 42min).

  • Average sunshine in December: 6h and 5min

The month with the most sunshine is January (Average sunshine: 9h and 6min).
The month with the least sunshine is November (Average sunshine: 6h and 42min).

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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).
The 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

The months with the highest UV index are January, February, March, April, July, September, November and December (UV index 7).
The 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

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

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