December weather forecast
Grantham, Jamaica

The first month of the winter, December, is also a moderately hot month in Grantham, Jamaica, with an average temperature varying between 21.5°C (70.7°F) and 28.9°C (84°F).

Temperature

The advent of December denotes an average high-temperature of a still warm 28.9°C (84°F), subtly different from November's 29.7°C (85.5°F). Throughout the month of December, Grantham reports a steady low-temperature average of 21.5°C (70.7°F).

Heat index

The average heat index in December is computed to be a very hot 35°C (95°F). Undertake extra safety actions, heat cramps and heat exhaustion are expected. Heatstroke may result from lengthy activity.
Observations indicate that the heat index values are for shady locations with light wind. Exposure to unobstructed sunshine could lead to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', offers an insight into how hot it feels when we factor in moisture content. A person's impression of weather can be swayed by numerous aspects, among them metabolic variations, pregnancy, and activity levels. Given direct exposure to sunlight, one might experience a rise in the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Children often overlook the need for breaks and fluid intake. Thirst is a late-stage sign of dehydration - hence, it is necessary to stay hydrated, especially during extended periods of physical activities.
Perspiring is a crucial mechanism for the human body, allowing it to release excessive warmth through evaporating sweat. When relative humidity is heightened, it slows the rate of evaporation, thereby decreasing the body's ability to shed heat and creating a sensation of overheating. Excessive heat gain, when not shed effectively by the body, can result in increasing body temperatures and related hazards.

Humidity

The months with the highest humidity in Grantham are October through December, with an average relative humidity of 81%.

Rainfall

In December, the rain falls for 19.9 days. Throughout December, 42mm (1.65") of precipitation is accumulated. In Grantham, during the entire year, the rain falls for 265.1 days and collects up to 806mm (31.73") of precipitation.

Daylight

The month with the shortest days is December, with an average of 11h and 6min of daylight.
On the first day of the month, sunrise is at 06:23 and sunset at 17:30. On the last day of December, sunrise is at 06:38 and sunset at 17:42 EST.

Sunshine

December has the least sunshine of the year in Grantham, with an average of 6.7h of sunshine.

UV index

January through April, September, November and December, with an average maximum UV index of 6, are months with the lowest UV index in Grantham. A UV Index of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV radiation for the average person.
Note: A daily high UV index of 6 in December leads to these guidelines:
Use protective steps and abide by sun safety guidelines. Safeguarding against skin and eye harm is necessary. Minimize exposure to direct sunlight and seek shade from 10 a.m. to 4 p.m., when UV radiation is most intense, but remember that shade structures may not offer complete protection. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.