December weather forecast
Cayo Guillermo, Cuba

As the curtain closes on the year in Cayo Guillermo comes December, featuring mild weather as winter takes hold. Reigning over weather statistics for this month are lower rainfall levels at 39mm (1.54"), substantiating the arrival of the dry season. Signifying the winter solstice, December sees the shortest daylight period, going down to 10.8 hours. As the UV index drops to 6, it indicates the diminished intensity of the sun's rays. While marking the end of the year, December subtly ushers in the weather nuances that will define the beginning of a whole new cycle.

Temperature

December's weather in Cayo Guillermo displays an average high-temperature of a still warm 28°C (82.4°F), slightly varied from November's 29°C (84.2°F). During the month of December, the temperature generally drops to a low average of 18°C (64.4°F).

Rainfall

The month with the least rainfall in Cayo Guillermo is December, when the rain falls for 7 days and typically collects 39mm (1.54") of precipitation.

Sea temperature

In Cayo Guillermo, the average seawater temperature in December is 26°C (78.8°F).
Note: Surface water temperatures ranging from 25°C (77°F) to 29°C (84.2°F) are considered superb and highly pleasant for water activities over extended periods.

Daylight

December has the shortest days of the year, with an average of 10h and 48min of daylight.
On the first day of December in Cayo Guillermo, sunrise is at 06:38 and sunset at 17:29. On the last day of the month, sunrise is at 06:54 and sunset at 17:41 CST.

Sunshine

The months with the least sunshine in Cayo Guillermo are January, February, June, September through December, with an average of 7h of sunshine.

UV index

December is the month with the lowest UV index in Cayo Guillermo, with an average maximum UV index of 6. A UV Index of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: The maximum UV index, 6 during December, leads to the following recommendations:
Beware of overexposure. Fair-skinned individuals risk burning in less than 20 minutes. It's important to stay in the shade and limit exposure to the sun from 10 a.m. to 4 p.m., when UV radiation is most intense, although remember that shade structures may not provide full sun protection. Opt for tightly woven and loose clothing to enhance protection from the Sun. Alert! The Sun's UV rays are heightened by the reflection of sand and water.