May weather forecast and climate
Vientiane, Laos

The last month of the spring, May, is another hot month in Vientiane, Laos, with average temperature varying between 24.6°C (76.3°F) and 33°C (91.4°F).

Temperature

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

Heat index

In May, the average heat index is appraised at a life-threatening hot 47.2°C (117°F). Be wary - heat exhaustion and heat cramps are highly anticipated. With continued activity, heatstroke is very likely.
Take into consideration that the heat index values are calculated for shade and light wind conditions. 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', 'feels like', 'real feel', or 'felt air temperature', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. Additional factors like wind, differences in body mass, height, and shape, pregnancy, and activity influence one's weather impression. 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. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.
The human body normally cools itself by perspiration, as evaporated sweat carries heat away from the body. 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 exceeds the level the body can remove, body temperature begins to rise, and heat-related illnesses and disorders may develop.

Humidity

The average relative humidity in May is 78%.

Rainfall

In Vientiane, in May, during 15 rainfall days, 245.8mm (9.7") of precipitation is typically accumulated. In Vientiane, during the entire year, the rain falls for 118 days and collects up to 1660.5mm (65.4") of precipitation.

Daylight

In Vientiane, Laos, the average length of the day is 13h.

Sunshine

In Vientiane, the average sunshine is 6.7h.

UV index

Months with the highest UV index in Vientiane, Laos, are March through September, with an average maximum UV index of 12. A UV Index value of 11, and more, symbolizes an excessive health risk from unsafe exposure to the UV radiation for the ordinary person.
Note: The daily maximum UV index of 12 interpret into the following advice:
Take all required precautions, as unprotected skin and eyes can burn in 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. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Even on cloudy days, a sunscreen with a minimum 30 sun protection factor should be generously applied and frequently re-applied, including after every swim or outdoor exercise.