December weather forecast
San Andres, El Salvador

The first month of the winter, December, is still a hot month in San Andres, El Salvador, with an average temperature ranging between min 18.6°C (65.5°F) and max 30.8°C (87.4°F).

Temperature

The advent of December sees the average high-temperature at a still hot 30.8°C (87.4°F), subtly shifted from November's 30.5°C (86.9°F). A considerable shift from the daytime highs is observed during December nights, with an average low of 18.6°C (65.5°F).

Heat index

December's mean heat index is appraised at a torrid 37°C (98.6°F). Implement heightened safety measures - risk of heat exhaustion and heat cramps is increased. Prolonged activity may result in heatstroke.
Research indicates the heat index considers values in shaded locales and with light winds. The heat index could see an increase by 15 Fahrenheit (8 Celsius) degrees under direct sunshine.
Note: The heat index, also known as 'felt air temperature' or 'feels like', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. The influence of weather can be personal, changing with an individual's body mass, height, and level of physical exertion. Exposure to direct sun rays can influence the heat you feel, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Juveniles often do not understand the need to recuperate and rehydrate. Thirst is a delayed symptom of dehydration - hence, it is vital to maintain hydration, particularly during ongoing physical activities.
The human body normally cools itself by perspiration, as evaporated sweat carries heat away from the body. Under conditions of high relative humidity, the rate of evaporation decreases. This results in the body retaining more heat than under conditions of dry air. As the body gains more heat than it can dissipate, there's a risk of increasing temperatures and resultant overheating.

Humidity

In December, the average relative humidity is 69%.

Rainfall

In San Andres, El Salvador, in December, during 3.3 rainfall days, 5mm (0.2") of precipitation is typically accumulated. In San Andres, during the entire year, the rain falls for 192.2 days and collects up to 1062mm (41.81") of precipitation.

Daylight

The month with the shortest days is December, with an average of 11h and 18min of daylight.
On the first day of the month, sunrise is at 06:05 and sunset at 17:27. On the last day of December, in San Andres, sunrise is at 06:21 and sunset at 17:40 CST.

Sunshine

The months with the least sunshine in San Andres are January and December, with an average of 7.7h of sunshine.

UV index

The months with the lowest UV index are January, June through December, with an average maximum UV index of 6. A UV Index value of 6 to 7 symbolizes a high health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: In December, the average maximum UV index of 6 translates into the following recommendations:
Avoid overexposure. Fair-skinned individuals can burn in under 20 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 optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.