The first month of the winter, December
, is also a moderately hot month in Cozumel
, with temperature in the range of an average low of 20.3°C (68.5°F) and an average high of 28.6°C (83.5°F).
The coldest months are January
and December, with an average high-temperature of 28.6°C (83.5°F).
The average heat index in December is appraised at a tropical 34°C (93.2°F). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.Note
: The heat index, also known as 'real feel', 'feels like', 'felt air temperature', or 'apparent temperature', combines air temperature and relative humidity to represent a human perceived temperature equivalent. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (differences in body mass, height, and shape, wind, clothing). Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
The average relative humidity in December in Cozumel is 83%.
In December, the rain falls for 9.8 days. Throughout December, 107mm (4.21") of precipitation is accumulated. In Cozumel, during the entire year, the rain falls for 119.9 days and collects up to 1490mm (58.66") of precipitation.
In Cozumel, the average seawater temperature in December is 27°C (80.6°F).Note
: For any water activity, surface water temperatures between 25°C (77°F) and 29°C (84.2°F) are considered as excellent and extremely pleasant for lengthened periods.
With an average of 10h and 55min of daylight, December has the shortest days of the year in Cozumel, Mexico.
On the first day of the month, sunrise is at 7:07 am and sunset at 6:06 pm. On the last day of December, in Cozumel, sunrise is at 7:23 am and sunset at 6:18 pm EST.
In Cozumel, the average sunshine in December is 6.2h.
January and December, with an average maximum UV index of 7, are months with the lowest UV index. A UV Index estimate of 6 to 7 represents a high health hazard from exposure to the Sun's UV radiation for average individuals.Note
: In December, the average maximum UV index of 7 translate into the following recommendations:
Take precautions against overexposure. Fair-skinned people may get burned in less than 20 minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.