May weather forecast
Bangkok, Thailand

Bangkok, Thailand goes through considerable meteorological changes during May. This period witnesses a massive surge in rainfall, reaching up to 248mm (9.76"), spread across a significant 16 days, marking the real onset of the monsoon season. The city, despite the decline in temperature, continues to experience high warmth, hinting at the tropical climate of Thailand. On the other hand, increased cloud cover results in reduced sunshine duration. Residents eagerly anticipate drier weather conditions as the significant rainfall continues into June.

Temperature

The commencement of May in Bangkok records an average high-temperature of a tropical 34.4°C (93.9°F), barely varying from April's 35.4°C (95.7°F). An average low-temperature of 26.3°C (79.3°F) is common in Bangkok during the nights of May.

Heat index

May's mean heat index is calculated to be a blazing hot 51°C (123.8°F). Heed: Expect heat cramps and heat exhaustion. Continued action may cause heatstroke.
From a standpoint of the heat index, values pertain to shaded conditions and mild breezes. Exposure to the direct sun could elevate the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', embodies the combination of air temperature and moisture content to illustrate perceived heat. One's perception of weather can be shaped by other factors, involving metabolic differences, pregnancy, and physical exertion. Recognize that direct exposure to the sun can escalate the heat effect, potentially adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are primarily vital for children. Typically, children face more danger than adults as they usually perspire less. Their larger skin surface relative to their small bodies and increased heat output from their activities enhance their risk.
Perspiring is a crucial mechanism for the human body, allowing it to release excessive warmth through evaporating sweat. During high air temperature and humidity (high heat index), the process of perspiration is hindered, intensifying the sensation of heat. Elevated heat gain compared to the body's release capability poses risks of dehydration and potential overheating.

Humidity

In May, the average relative humidity in Bangkok is 75%.

Rainfall

In Bangkok, during May, the rain falls for 16 days and regularly aggregates up to 248mm (9.76") of precipitation. Throughout the year, there are 128 rainfall days, and 1648mm (64.88") of precipitation is accumulated.

Sea temperature

The month with the warmest seawater in Bangkok is May, with an average sea temperature of 29.9°C (85.8°F).
Note: Water activities in temperatures ranging from 25°C (77°F) to 29°C (84.2°F) are pleasurable, without feeling uncomfortable even during extended periods.

Daylight

In Bangkok, the average length of the day in May is 12h and 46min.
On the first day of the month, sunrise is at 05:56 and sunset at 18:33. On the last day of May, sunrise is at 05:49 and sunset at 18:42 +07.

Sunshine

In Bangkok, Thailand, the average sunshine in May is 7h.

UV index

February through September, with an average maximum UV index of 12, are months with the highest UV index in Bangkok. A UV Index reading of 11, and higher, represents an ultimate health vulnerability from unprotected exposure to Sun's UV rays for the average person.
Note: The daily maximum UV index of 12 in May interprets into the following advice:
Practice all-important precautions. Light skin people may get burned in less than 5 minutes. To the best of your ability, limit your exposure to the sun between the hours of 10 a.m. and 4 p.m., when UV radiation is at its peak. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat. Following every swim or outdoor workout, a sunscreen with an SPF of not less than 30 should be liberally applied and re-applied frequently, even on overcast days. Caution! The mirror effect of sand and water ups the UV radiation strength.