December weather forecast
Hagåtña, GU

Welcoming December, Hagåtña, Guam presents a delightful medley of warm tropical weather and seasonal festivities. The city starts bracing for the holiday season with an air of anticipation and joy. A further reduction in rainfall to 2.99" (76mm) over 22.8 days provides the perfect backdrop for holiday shopping, Christmas parades, and festive celebrations. With relative comfort, festive spirit, and astounding visual appeal, December offers a unique and mesmerising experience, concluding the calendar year on a high and joyful note.

Temperature

The arrival of December denotes a barely perceptible change in the average high-temperatures to a still moderately hot 83.5°F (28.6°C) from November's 84.2°F (29°C). During December's nights, Hagåtña notes a minor temperature decline, reaching an average of 82°F (27.8°C).

Heat index

Throughout December, the heat index is appraised at a hot 91.4°F (33°C). More preventive actions are needed, risk of heat exhaustion and heat cramps is significant. Prolonged activity may trigger heatstroke.
Take note of the fact that heat index values are based on shaded circumstances with light airflows. An exposure to direct sunlight may lift the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'apparent temperature', binds temperature metrics with humidity values to give a sense of the actual warmth. A person's impression of weather can be swayed by numerous aspects, among them metabolic variations, pregnancy, and activity levels. Always consider that direct sunlight exposure might heighten the heat's effects, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to babies and toddlers. Children often do not understand the need to rest and hydrate. Thirst is a late manifestation of dehydration - therefore, it is essential to stay hydrated, particularly during prolonged physical activities.

Humidity

The months with the highest humidity are January, March through May, October through December, with an average relative humidity of 78%.

Rainfall

In Hagåtña, in December, it is raining for 22.8 days, with typically 2.99" (76mm) of accumulated precipitation. In Hagåtña, during the entire year, the rain falls for 288.5 days and collects up to 60.08" (1526mm) of precipitation.

Ocean temperature

In Hagåtña, Guam, the average seawater temperature in December is 83.1°F (28.4°C).
Note: Swimming, diving, and other water-related activities in temperatures between 77°F (25°C) and 84.2°F (29°C) are considered highly enjoyable and satisfying for longer durations without uneasiness.

Daylight

December has the shortest days of the year, with an average of 11h and 18min of daylight.
On the first day of December, sunrise is at 6:28 am and sunset at 5:51 pm. On the last day of the month, sunrise is at 6:43 am and sunset at 6:04 pm ChST.

Sunshine

The average sunshine in December is 6.5h.

UV index

January through August, October through December, with an average maximum UV index of 7, are months with the highest UV index. A UV Index estimate of 6 to 7 represents a high health vulnerability from exposure to the Sun's UV radiation for ordinary individuals.
Note: In December, a regular UV index of 7 translates into these guidelines:
Employ safeguards and advocate sun safety protocols. Shielding against skin and eye damage is crucial. Stay in the shade and limit sun exposure from 10 a.m. to 4 p.m., when UV radiation is most potent. Keep in mind that shade structures like parasols or canopies do not offer full protection. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key. Alert! Sand and water increase UV exposure due to their reflective properties.