January weather forecast
Hagåtña, GU

Step into the new year in Hagåtña, Guam with a pleasant tropical climate, dominating the city throughout the month. Here, the days remain warm, though the evenings bring a couple of degrees drop providing a comfortable respite. A mix of clear skies and overcast days are anticipated with a moderate chance of breezy winds. January experiences the broad swing of relative humidity from a mild 77% to a high 78%. This is combined with an average of 21.3 rainy days, recording an accumulated rainfall of 2.83" (72mm), an adequate amount to keep the region lush and green.

Temperature

At the start of January, Hagåtña's average high-temperature reaches a still warm 82°F (27.8°C), subtly different from the preceding month. During the January nights, Hagåtña's temperature maintains an average close to the daytime highs, settling at a still moderately hot 80.6°F (27°C).

Heat index

In January, the heat index is appraised at a tropical 87.8°F (31°C). A sense of exhaustion might occur with extended exposure and activity, potentially causing heat cramps.
Take into consideration that the heat index values are calculated for shade and light wind conditions. 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', binds temperature metrics with humidity values to give a sense of the actual warmth. Elements such as metabolic variations, being pregnant, and physical activity can impact one's weather perception. In direct sunlight, the heat's impact can be heightened, potentially leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Juveniles often do not understand the need to recuperate and rehydrate. Thirst is a delayed symptom of dehydration - hence, it is vital to maintain hydration, particularly during ongoing physical activities.

Humidity

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

Rainfall

In Hagåtña, during January, the rain falls for 21.3 days and regularly aggregates up to 2.83" (72mm) of 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, in January, the average water temperature is 82.9°F (28.3°C).
Note: Water temperature ranging between 77°F (25°C) and 84.2°F (29°C) is considered very warm and pleasing for everyone. It allows for enjoyable water activities over extended periods without discomfort.

Daylight

In Hagåtña, the average length of the day in January is 11h and 26min.
On the first day of the month, sunrise is at 6:43 am and sunset at 6:04 pm. On the last day of January, sunrise is at 6:47 am and sunset at 6:20 pm ChST.

Sunshine

In Hagåtña, Guam, the average sunshine in January is 7.6h.

UV index

The months with the highest UV index are January through August, October through December, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to UV radiation for the ordinary person.
Note: An average maximum UV index of 7 in January leads to these recommendations:
Implement precautions and maintain sun safety methods. Avoidance of sunburn is demanded. 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. Tightly woven clothing, when worn loosely, shields effectively against the Sun. Notice! The reflection of water and sand increases the UV radiation significantly.