December weather forecast
Jaco, Costa Rica

December in Jaco, Costa Rica, signals the arrival of the much-awaited dry season. The month witnesses a significant decrease in rainfall to 41mm (1.61"), a stark contrast to the preceding wet months. Longer sunlight hours, decreased cloud cover, and lower humidity present an attractive weather combination for visitors. Sea temperatures remain stubbornly warm, providing the perfect setting for water activities. With a slight increase in wind speeds, days become more pleasant and nights more refreshing.

Temperature

Jaco, Costa Rica, observes a minor difference in average high-temperatures between November's 28.3°C (82.9°F) and December's 28.7°C (83.7°F). In Jaco, nights during December observe an average temperature decrease to a still moderately hot 24.6°C (76.3°F).

Heat index

In December, the heat index is estimated at a hot 33°C (91.4°F). Implement more safety precautions, heat cramps and heat exhaustion may happen. Persistent activity could induce heatstroke.
In terms of the heat index, values are set with light wind and shade conditions in mind. When under direct sunshine, the heat index may be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'feels like', stands as a testimony to how temperature and humidity combine to impact our sense of warmth. The impact of weather is personal, differing among a variety of people based on differences in body mass, height, and the level of physical exertion. With direct sunlight, be aware that it might enhance the heat sensation, raising the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are of high significance for children. Young children are more at risk than adults since they tend to sweat less. Moreover, their large skin surface in proportion to their small bodies and the high heat production due to their activities contribute to their vulnerability.

Humidity

The average relative humidity in December in Jaco, Costa Rica, is 75%.

Rainfall

In Jaco, during December, the rain falls for 16.3 days and regularly aggregates up to 41mm (1.61") of precipitation. In Jaco, during the entire year, the rain falls for 236.2 days and collects up to 1501mm (59.09") of precipitation.

Sea temperature

In Jaco, in December, the average water temperature is 28.2°C (82.8°F).
Note: Swimming, diving, and other water-related activities in temperatures between 25°C (77°F) and 29°C (84.2°F) are considered highly enjoyable and satisfying for longer durations without uneasiness.

Daylight

With an average of 11h and 36min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 05:39 and sunset at 17:15. On the last day of the month, sunrise is at 05:54 and sunset at 17:29 CST.

Sunshine

The average sunshine in December in Jaco, Costa Rica, is 9.4h.

UV index

January through December, with an average maximum UV index of 7, are months with the highest UV index in Jaco. The months with the lowest UV index are January through December, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to UV radiation for the average person.
Note: The UV index of 7 during December translates into the following guidance:
Embrace precautions and observe sun safety norms. Evasion of sunburn is a necessity. 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. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Caution! The reflection of sand and water significantly amplifies the Sun's UV radiation.