May 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 May

The last month of the spring, May, is another tropical month in Colombo, Sri Lanka, with average temperature ranging between max 30.6°C (87.1°F) and min 26.3°C (79.3°F).

Temperature

In May, the average high-temperature is relatively the same as in April - a still hot 30.6°C (87.1°F). In May, in Colombo, the average low-temperature is 26.3°C (79.3°F).

Heat index

The average heat index in May is calculated to be a very hot 39.9°C (103.8°F). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Note that heat index values are valued for light wind and location in the shade. 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 'real feel', 'feels like', 'felt air temperature', or 'apparent temperature', combines air temperature and relative humidity to represent a human perceived temperature equivalent. This effect is individual, with diverse people perceiving weather differently for numerous reasons (wind, differences in body mass, height, and shape, metabolic differences), and activity. 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. 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 Colombo is 81%.

Rainfall

In Colombo, in May, during 28.8 rainfall days, 306mm (12.05") of precipitation is typically 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 29.3°C (84.7°F).
Note: Water temperature between 25°C (77°F) and 29°C (84.2°F) is regarded as very warm and enjoyable by all. With these temperatures, water activities are pleasurable, without feeling uncomfortable for prolonged periods.

Daylight

The average length of the day in May is 12.4h.

Sunshine

The average sunshine in Colombo is 8.6h.

UV index

May, June, August and October, with an average maximum UV index of 6, are months with the lowest UV index in Colombo. A UV Index reading of 6 to 7 represents a high health risk from unsafe exposure to the UV radiation for ordinary individuals.
Note: The daily maximum UV index of 6 interpret into the following advice:
Take precautions against overexposure. Protection against sun damage is needed. 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. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.
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FAQ

What is the temperature in May in Colombo?

In May, the average high-temperature is 30.6°C (87.1°F), and the average low-temperature is 26.3°C (79.3°F). The average heat index (a.k.a. 'feels like', 'real feel'), which factors the actual air temperature with the relative humidity, in May is calculated to be 39.9°C (103.8°F).

What is the average humidity in May in Colombo?

The average relative humidity in May in Colombo is 81%.

How much does it rain in Colombo in May?

In May, the rain falls for 28.8 days. Throughout May, 306mm (12.05") of precipitation is accumulated.

How warm is the water in May in Colombo?

In Colombo, Sri Lanka, the average seawater temperature in May is 29.3°C (84.7°F). 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.

How many hours of daylight does Colombo have in May?

The average length of the day in May is 12.4h.

How many hours of sunshine does Colombo have in May?

In Colombo, the average sunshine in May is 8.6h.

When is the lowest UV index in Colombo?

May, June, August and October, with an average maximum UV index of 6, are months with the lowest UV index.

What is the UV index intensity in May in Colombo?

In Colombo, the average daily maximum UV index in May is 6. A UV Index reading of 6 to 7 represents a high health risk from unsafe exposure to the Sun's UV rays.

Average temperature in May
Colombo, Sri Lanka

Average temperature in May - Colombo, Sri Lanka
  • Average high temperature in May: 30.6°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 May: 26.3°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 May
Colombo, Sri Lanka

Average pressure in May - Colombo, Sri Lanka
  • Average pressure in May: 1008.6mbar

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 May
Colombo, Sri Lanka

Average wind speed in May - Colombo, Sri Lanka
  • Average wind speed in May: 12.9km/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 May
Colombo, Sri Lanka

Average humidity in May - Colombo, Sri Lanka
  • Average humidity in May: 81%

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 May
Colombo, Sri Lanka

Average rainfall in May - Colombo, Sri Lanka
  • Average rainfall in May: 306mm

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 May
Colombo, Sri Lanka

Average rainfall days in May - Colombo, Sri Lanka
  • Average rainfall days in May: 28.8 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 May
Colombo, Sri Lanka

Average sea temperature in May - Colombo, Sri Lanka
  • Average sea temperature in May: 29.3°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 May /
Average sunshine in May
Colombo, Sri Lanka

Average daylight in May / Average sunshine in May - Colombo, Sri Lanka
  • Average daylight in May: 12.4h

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 May: 8.6h

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 May
Colombo, Sri Lanka

Average sunshine days in May - Colombo, Sri Lanka
  • Average sunshine days in May: 1.3 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 May
Colombo, Sri Lanka

Average UV index in May - Colombo, Sri Lanka
  • Average UV index in May: 6

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 May
Colombo, Sri Lanka

Average cloud cover in May - Colombo, Sri Lanka
  • Average cloud cover in May: 54

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 May
Colombo, Sri Lanka

Average visibility in May - Colombo, Sri Lanka
  • Average visibility in May: 9km

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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