December weather forecast and climate
Hagåtña, GU

Weather in December

December, the first month of the winter, in Hagåtña, is also a moderately hot month, with average temperature varying between 82°F (27.8°C) and 83.5°F (28.6°C).

Temperature

In Hagåtña, the average high-temperature is almost the same as in November - a still warm 83.5°F (28.6°C). The average low-temperature, in December, is 82°F (27.8°C).

Heat index

In December, the average heat index is estimated at a tropical 91.9°F (33.3°C). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Take into consideration that the heat index values are calculated for shade and light wind conditions. With the exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'real feel', 'feels like', or 'felt air temperature', is a measure that combines both air temperature and relative humidity into a single value that indicates how hot the weather feels. Additional factors like activity, wind, differences in body mass, height, and shape, and metabolic differences affect individual temperature impact. Be aware that direct exposure to sunlight increases heat impact, and may raise the heat index additionally, by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.

Humidity

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

Rainfall

In Hagåtña, during December, the rain falls for 22.8 days and regularly aggregates up to 2.99" (76mm) of precipitation. Throughout the year, there are 288.5 rainfall days, and 60.08" (1526mm) of precipitation is accumulated.

Ocean temperature

In December, the average ocean temperature in Hagåtña is 83.1°F (28.4°C).
Note: Water temperature between 77°F (25°C) and 84.2°F (29°C) is regarded as very warm and enjoyable by all. With these temperatures, water activities are pleasurable, without feeling uncomfortable for prolonged periods.

Daylight

December has the shortest days of the year, with an average of 11.3h of daylight.

Sunshine

In Hagåtña, 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 value of 6 to 7 symbolizes a high health risk from the exposure to the Sun's UV rays for the ordinary person.
Note: The average daily UV index of 7 transform into the following instructions:
Take precautions against overexposure. Protection against sun damage is needed. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.
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FAQ

What is the temperature in December in Hagåtña?

The average high-temperature, in December, in Hagåtña, Guam, is 83.5°F (28.6°C), while the average low-temperature is 82°F (27.8°C). In December, the average heat index (a.k.a. 'real feel', 'apparent temperature'), that calculates temperature value influenced by the moisture in the air, is evaluated at 91.9°F (33.3°C).

What are the most humid months in Hagåtña?

Months with the highest humidity in Hagåtña are January, March through May, October through December, with an average relative humidity of 78%.

What is the average humidity in December in Hagåtña?

In Hagåtña, Guam, the average relative humidity in December is 78%.

How much does it rain in Hagåtña in December?

In Hagåtña, Guam, in December, during 22.8 rainfall days, 2.99" (76mm) of precipitation is typically accumulated.

What is the ocean temperature in December in Hagåtña?

In December, the average ocean temperature is 83.1°F (28.4°C). For swimming, diving, and other water activities, temperatures between 77°F (25°C) and 84.2°F (29°C) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

What is the month with the shortest days in Hagåtña?

December has the shortest days of the year in Hagåtña, Guam, with an average of 11.3h of daylight.

What is the average length of the day in December in Hagåtña?

In Hagåtña, Guam, the average length of the day in December is 11.3h.

How many hours of sunshine does Hagåtña have in December?

In Hagåtña, Guam, the average sunshine in December is 6.5h.

When is the highest UV index in Hagåtña?

Months with the highest UV index in Hagåtña are January through August, October through December, with an average maximum UV index of 7.

How high is the UV index in December in Hagåtña?

The average daily maximum UV index in December in Hagåtña, Guam, is 7. A UV Index value of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to the Sun's UV rays.

Average temperature in December
Hagåtña, GU

Average temperature in December - Hagåtña, GU
  • Average high temperature in December: 83.5°F

The warmest months (with the highest average high temperature) are July and August (84.7°F).
The month with the lowest average high temperature is February (81.7°F).

  • Average low temperature in December: 82°F

The month with the highest average low temperature is June (83.3°F).
The coldest month (with the lowest average low temperature) is February (79.7°F).

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Average pressure in December
Hagåtña, GU

Average pressure in December - Hagåtña, GU
  • Average pressure in December: 29.83"

The month with the highest atmospheric pressure is February (29.88").
Months with the lowest atmospheric pressure are August, September and October (29.79").

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Average wind speed in December
Hagåtña, GU

Average wind speed in December - Hagåtña, GU
  • Average wind speed in December: 15.7mph

The windiest month (with the highest average wind speed) is February (16.3mph).
The calmest month (with the lowest average wind speed) is August (9.6mph).

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Average humidity in December
Hagåtña, GU

Average humidity in December - Hagåtña, GU
  • Average humidity in December: 78%

Months with the highest relative humidity are January, March, April, May, October, November and December (78%).
The month with the lowest relative humidity is August (76%).

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Average rainfall in December
Hagåtña, GU

Average rainfall in December - Hagåtña, GU
  • Average rainfall in December: 2.99"

The wettest month (with the highest rainfall) is September (10.28").
The driest month (with the least rainfall) is March (1.81").

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Average rainfall days in December
Hagåtña, GU

Average rainfall days in December - Hagåtña, GU
  • Average rainfall days in December: 22.8 days

Months with the highest number of rainy days are July and August (28.9 days).
The month with the least rainy days is February (17.5 days).

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Average sea temperature in December
Hagåtña, GU

Average sea temperature in December - Hagåtña, GU
  • Average sea temperature in December: 83.2°F

The best month for swimming (with the highest average sea temperature) is August (85.4°F).
The coldest month (with the lowest average sea temperature) is February (82°F).

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Average daylight in December /
Average sunshine in December
Hagåtña, GU

Average daylight in December / Average sunshine in December - Hagåtña, GU
  • Average daylight in December: 11.3h

The month with the longest days is June (Average daylight: 12.9h).
The month with the shortest days is December (Average daylight: 11.3h).

  • Average sunshine in December: 6.5h

The month with the most sunshine is June (Average sunshine: 10.6h).
The month with the least sunshine is November (Average sunshine: 6.3h).

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Average sunshine days in December
Hagåtña, GU

Average sunshine days in December - Hagåtña, GU
  • Average sunshine days in December: 4.7 days

The month with the most sunshine days is March (6.6 days).
The month with the least sunshine days is September (1.1 days).

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Average UV index in December
Hagåtña, GU

Average UV index in December - Hagåtña, GU
  • Average UV index in December: 7

Months with the highest UV index are January, February, March, April, May, June, July, August, October, November and December (UV index 7).
The month with the lowest UV index is September (UV index 6).

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Average cloud cover in December
Hagåtña, GU

Average cloud cover in December - Hagåtña, GU
  • Average cloud cover in December: 44

Months with the most cloud cover are January, August and October (Cloud cover 46).
Months with the least cloud cover are May and June (Cloud cover 39).

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Average visibility in December
Hagåtña, GU

Average visibility in December - Hagåtña, GU
  • Average visibility in December: 6mi

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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