May weather forecast
Vientiane, Laos

May, the last month of the spring in Vientiane, is another tropical month, with an average temperature ranging between min 24.6°C (76.3°F) and max 33°C (91.4°F).

Temperature

In May, the average high-temperature is almost the same as in April - a still tropical 33°C (91.4°F). In Vientiane, Laos, the average low-temperature is 24.6°C (76.3°F).

Heat index

The average heat index in May is evaluated at a blazing hot 47.2°C (117°F). Be wary: Heat exhaustion and heat cramps are highly anticipated. With continued activity, heatstroke is very likely.
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', 'feels like', or 'felt air temperature', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. This effect is individual, with diverse people perceiving weather differently for numerous reasons (clothing, wind, 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.
To prevent overheating and help regulate its internal temperature, the human body sweat and rely on the evaporation to cool down. A higher relative humidity affects normal body cooling by reducing the evaporation rate, subsequently lowering the rate at which the body cools and increasing the perception of heat. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

The average relative humidity in May in Vientiane is 78%.

Rainfall

In Vientiane, during 15 rainfall days, 245.8mm (9.68") of precipitation is typically accumulated. In Vientiane, during the entire year, the rain falls for 118 days and collects up to 1660.5mm (65.37") of precipitation.

Daylight

In May, the average length of the day is 12h and 59min.
On the first day of the month, sunrise is at 05:42 and sunset at 18:30. On the last day of May, sunrise is at 05:33 and sunset at 18:40 +07.

Sunshine

In May, the average sunshine is 6.7h.

UV index

The months with the highest UV index in Vientiane are March through September, with an average maximum UV index of 12. A UV Index reading of 11, and higher, represents an excessive health risk from exposure to the Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 12 in May interpret into the following advice:
Practice all essential precautions. Protection against sun damage is crucial. 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. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. A broad-spectrum sunscreen of SPF 30+ should be liberally applied and re-applied every two hours, and immediately after an outdoor workout or a swim.