December weather forecast
Arroyo, PR

December in Arroyo brings the year to a comfortable close, with mild temperatures and a significant reduction in rainfall to 1.61" (41mm). The cooler nights and warm sunny days mark the onset of the holiday season. Despite shorter days, the consistently moderate sea temperature ensures the continued enjoyment of aquatic activities. December's weather sets the ideal backdrop for spending time outdoors, whether it's celebrating festivities or soaking in the natural beauty of the region. The steady wind keeps the climate comfortable, rounding off an eventful meteorological year in Arroyo, Puerto Rico.

Temperature

Arroyo's December average high-temperature settles at a still moderately hot 80.8°F (27.1°C), showing a near match with the preceding month. December in Arroyo witnesses a minor deviation from daytime peaks, with an average nighttime temperature of 72.9°F (22.7°C).

Heat index

The average heat index in December is evaluated at a hot 86°F (30°C). Persistent activity under exposure might lead to a feeling of weariness, with subsequent heat cramps.
Realize that the values for the heat index are set for shaded places and light winds. Direct sunlight exposure may cause a 15 Fahrenheit (8 Celsius) degrees rise in the heat index.
Note: The heat index, also known as 'feels like' or 'apparent temperature', takes into account both air temperature and humidity to illustrate what people actually feel. Physical activity, clothing, and metabolic variations are additional factors that impact an individual's perception of temperature. Direct sun rays can make one feel hotter, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold great significance to children. Young people are generally more susceptible than adults because they perspire less. Furthermore, their proportionally larger skin surface to their petite bodies and the increased heat output from their actions add to the risk.

Humidity

In Arroyo, the average relative humidity in December is 80%.

Rainfall

In Arroyo, in December, during 18.9 rainfall days, 1.61" (41mm) of precipitation is typically accumulated. Throughout the year, there are 255.3 rainfall days, and 29.41" (747mm) of precipitation is accumulated.

Ocean temperature

In Arroyo, the average seawater temperature in December is 82°F (27.8°C).
Note: Surface water temperatures ranging from 77°F (25°C) to 84.2°F (29°C) are seen as ideal and highly pleasant for extended enjoyment in all water activities.

Daylight

December has the shortest days of the year, with an average of 11h and 6min of daylight.
On the first day of the month, sunrise is at 6:39 am and sunset at 5:47 pm. On the last day of December, in Arroyo, Puerto Rico, sunrise is at 6:55 am and sunset at 5:59 pm AST.

Sunshine

The month with the least sunshine is December, with an average of 6.5h of sunshine.

UV index

January through April, November and December, with an average maximum UV index of 6, are months with the lowest UV index in Arroyo. A UV Index value of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV radiation for the average person.
Note: The UV index of 6 during December translates into the following guidance:
Skirt overexposure. People with light complexions might get scorched in under 20 minutes. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a period when UV radiation is particularly strong, noting that parasols or canopies may not offer total sun protection. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days. Alert! UV radiation becomes sharper due to reflections from sand and water.