May weather forecast
Ko Samui, Thailand

Ko Samui, Thailand, sees May as a month featuring the year's first significant jump in rainfall to 156mm (6.14"). The pre-monsoon showers lead to a more comfortable and enjoyable climate in the region. The sea remains warm and inviting despite the uptick in rainfall. This increase also results in a slight decrease in daylight hours, a trend that carries into the coming months. Visitors can look forward to enjoying the rain-cooled breeze at this time.

Temperature

Ko Samui's weather in May, with an average high-temperature of a still tropical 32.5°C (90.5°F), subtly shifts from April's 32.6°C (90.7°F). Nighttime temperatures in Ko Samui consistently average a moderately hot 25.7°C (78.3°F) during May.

Heat index

During May, the heat index is computed to be a blazing hot 46°C (114.8°F). Vigilance: Heat cramps and heat exhaustion are likely. The likelihood of heatstroke increases with continued activity.
In terms of the heat index, values are set with light wind and shade conditions in mind. An exposure to direct sunlight may lift the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'feels like', melds the effects of warmth and moisture to generate a feeling of heat. The influence of weather is personal, differing among a variety of individuals based on differences in body mass, stature, and the level of physical activity. It is noteworthy that being in direct sunlight can enhance the weather's impact, raising the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are essentially critical for children. Youngsters frequently overlook the need for breaks and fluid intake. Thirst is an advanced sign of dehydration - thereby highlighting the importance of keeping hydrated, particularly during long physical activities.
The process of perspiration is vital for the human body to get rid of excess warmth by allowing sweat to evaporate. Under conditions of high temperature and humidity (enhanced heat index), sweat production is compromised, exacerbating the sensation of warmth. When the heat gained surpasses the body's cooling capacity, temperatures rise, signaling potential health concerns.

Humidity

The average relative humidity in May is 80%.

Rainfall

In Ko Samui, in May, during 16 rainfall days, 156mm (6.14") of precipitation is typically accumulated. In Ko Samui, during the entire year, the rain falls for 160 days and collects up to 1960mm (77.17") of precipitation.

Sea temperature

With an average sea temperature of 30.1°C (86.2°F), May is the month with the warmest seawater in Ko Samui.
Note: Many feel that waters warmer than 30°C (86°F) fail to offer the same rejuvenating touch.

Daylight

In Ko Samui, the average length of the day in May is 12h and 34min.
On the first day of May, sunrise is at 06:02 and sunset at 18:31. On the last day of the month, sunrise is at 05:58 and sunset at 18:36 +07.

Sunshine

May through December, with an average of 6h of sunshine, are months with the least sunshine in Ko Samui, Thailand.

UV index

February through October, with an average maximum UV index of 12, are months with the highest UV index. A UV Index estimate of 11, and higher, represents an excessive health risk from exposure to the Sun's UV rays for the average person.
Note: The UV index of 12 during May leads to these advisories:
Implement all necessary safeguards, unprotected skin might suffer burns rapidly. The hours from 10 a.m. to 4 p.m. have the most intense UV radiation. As much as possible, limit direct sun exposure during this period. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Even when it's cloudy, ensure the generous application and frequent reapplication of a sunscreen with at least 30 SPF, particularly post swim or outdoor activity. Attention! UV strength is notably upped by the reflection of sand and water.