May weather forecast
San Marcos, El Salvador

May presents a dramatic increase in rainfall to 267mm (10.51"); a significant upsurge from 53mm (2.09") experienced in April. This heavy rain, covering over 26 days, coupled with decreased sunshine hours, is a clear sign of the peak wet season. Outdoor activities may be compromised due to the high chances of getting caught in the rain. Furthermore, the increase in relative humidity to 76% can bring a rather muggy feel during this period. Conversely, a reduced wind speed adds a calming element to the intensified weather conditions.

Temperature

The dawn of May sees an average high-temperature of a still tropical 31.8°C (89.2°F), subtly contrasting with April's 33.4°C (92.1°F). During May nights, San Marcos records an average temperature of 22.6°C (72.7°F).

Heat index

May's average heat index is computed to be a blistering 42°C (107.6°F). Incorporate special precautions, risk of heat exhaustion and heat cramps is substantial. Sustained activity could cause heatstroke.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Direct exposure to sunshine could lead to a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. One's perception of temperature is subjective, varying based on their activity and individual heat perception, influenced by factors like wind, clothing, and metabolic variations. Always consider that direct sunlight exposure might heighten the heat's effects, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Children frequently underestimate the importance of resting and drinking fluids. Thirst is a symptom of advanced dehydration - hence the need to hydrate regularly, especially during protracted physical exercises.
Through perspiration, the body has a natural mechanism to eliminate excessive heat via sweat evaporation. An increase in relative humidity hinders the body's normal cooling function by reducing evaporation, thereby decreasing the rate of body cooling and enhancing the sense of warmth. Temperature imbalances caused by excessive heat retention can trigger heat-related maladies.

Humidity

In May, the average relative humidity is 76%.

Rainfall

The month with the most rainfall is May, when the rain falls for 26.9 days and typically aggregates up to 267mm (10.51") of precipitation.

Daylight

In May, the average length of the day is 12h and 46min.
On the first day of May, sunrise is at 05:34 and sunset at 18:12. On the last day of the month, sunrise is at 05:28 and sunset at 18:20 CST.

Sunshine

In May, the average sunshine in San Marcos is 10.7h.

UV index

The months with the lowest UV index in San Marcos are May through December, with an average maximum UV index of 6. A UV Index value of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV rays for the average person.
Note: The average daily UV index of 6 in May transforms into the following instructions:
Stand by precautions and apply sun safety measures. Evading sunburn is of great importance. Avoid direct Sun exposure and seek shade from 10 a.m. to 4 p.m., the period of highest UV radiation. Remember, however, that not all shade structures offer full protection. Opt for tightly woven and loose clothing to enhance protection from the Sun.