December weather forecast
Merizo, GU

December conclusively concludes the volatile weather transition from the wet to the dry season. The lower rainfall value of 2.99" (76mm) underlines the approach towards the dry spell. Consequently, a considerable increase in wind speed to 15.7 MPH, coupled with a dip in sea temperature, further marks the shift from the rainy season. Despite these changes, December enjoys consistent humidity and pressure levels, typical of a tropical climate. As the year winds down, the weather conditions pave the way for welcoming visitors seeking a tropical winter escape.

Temperature

The transition from November to December sees average high-temperatures adjusting to a still moderately hot 83.5°F (28.6°C), from a not significantly different 84.2°F (29°C). In Merizo, December nights experience a modest descent in temperature from daily peaks, cooling down to an average of 82°F (27.8°C).

Heat index

December's heat index is evaluated at a tropical 91.4°F (33°C). Undertake enhanced precautions, heat exhaustion and heat cramps are possible risks. Continuous activity could trigger heatstroke.
It is important to note that the heat index values are for shaded areas and light wind scenarios. Exposure to the sun directly might heighten the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'real feel', offers an insight into how hot it feels when we factor in moisture content. The influence of weather is personal, with a diverse population experiencing it differently due to differences in body mass, stature, and degree of activity. Given the impact of direct sunlight, it's noteworthy that the felt temperature can rise by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Kids are generally in more danger than adults because they perspire less. Their large skin surface area compared to their small bodies and the excessive heat due to their actions raises their risk.

Humidity

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

Rainfall

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

Ocean temperature

In December, the average ocean temperature is 83.1°F (28.4°C).
Note: Temperatures between 77°F (25°C) and 84.2°F (29°C) are ideal for swimming, diving, and similar water activities, ensuring pleasure and comfort for extended periods without feeling uneasy.

Daylight

With an average of 11h and 24min of daylight, December has the shortest days of the year in Merizo.
On the first day of the month, sunrise is at 6:28 am and sunset at 5:52 pm. On the last day of December, in Merizo, sunrise is at 6:43 am and sunset at 6:05 pm ChST.

Sunshine

In Merizo, Guam, 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 risk from unprotected exposure to Sun's UV rays for the average person.
Note: A maximum high UV index of 7 in December translates into the following recommendations:
Elude overexposure. Fair-skinned people could get burnt in less than 20 minutes. UV radiation from the sun is at its strongest between 10 a.m. and 4 p.m. Try to limit direct exposure during these hours. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage. Attention! UV strength is notably upped by the reflection of sand and water.