December weather forecast
Guam, USA

December in Guam ushers in the full onset of the dry season. The island experiences temperatures generally hovering between 79°F (26.1°C) and 86°F (30°C). As the month unfolds, rainfall becomes a rarer event, and the familiar high humidity of the wet season noticeably recedes, providing more agreeable conditions.

Throughout Guam, December's serene climate is evident. The land, which had been regularly drenched for the majority of the year, starts to thrive under more prolonged sunny intervals. The transition from the intermittent rains of November to the clearer skies of December firmly establishes the beginning of the dry period.

While occasional rain showers are still possible in December, they're significantly less frequent and intense than during the wet season. The steadfast northeast trade winds, flowing from 10mph (16.1km/h) to 20mph (32.2km/h), continue to grace the island with their cooling influence, mitigating the potential heat and ensuring the atmosphere remains pleasant.

The surrounding ocean waters of Guam, consistently warm throughout the year, offer an inviting allure in December. Their calm demeanor during this month is ideal for sea enthusiasts, whether it be swimmers, divers, or those simply wanting to relax by the shore. As December progresses, the consistent dry and sunlit conditions set the tone for the subsequent months, offering residents and visitors a respite from the earlier, more tumultuous weather patterns.

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• Hagåtña - December »
  The months with the highest humidity are January, March through May, October through December, with an average relative humidity of 78%. January through August, October through December, with an average maximum UV index of 7, are months with the highest UV index in Hagåtña, Guam.
• Dededo - December »
  The months with the highest humidity in Dededo are January, March through May, October through December, with an average relative humidity of 78%. The month with the shortest days in Dededo is December, with an average of 11h and 18min of daylight.
• Santa Rita - December »
  January, March through May, October through December, with an average relative humidity of 78%, are most humid months in Santa Rita, Guam. January through August, October through December, with an average maximum UV index of 7, are months with the highest UV index in Santa Rita.
• Agat - December »
  January, March through May, October through December, with an average relative humidity of 78%, are most humid months in Agat, Guam. The months with the highest humidity in Agat are January, March through May, October through December, with an average relative humidity of 78%.
• Piti - December »
  January, March through May, October through December, with an average relative humidity of 78%, are the most humid months in Piti, Guam. The months with the highest humidity in Piti are January, March through May, October through December, with an average relative humidity of 78%.
• Talofofo - December »
  The months with the highest humidity in Talofofo are January, March through May, October through December, with an average relative humidity of 78%. The month with the shortest days in Talofofo is December, with an average of 11h and 24min of daylight.
• Inarajan - December »
  January through August, October through December, with an average maximum UV index of 7, are months with the highest UV index in Inarajan. The months with the highest UV index in Inarajan are January through August, October through December, with an average maximum UV index of 7.
• Merizo - December »
  January, March through May, October through December, with an average relative humidity of 78%, are most humid months in Merizo. In Merizo during December, the rain falls for 22.8 days and regularly aggregates up to 2.99" (76mm) of precipitation.
• Umatac - December »
  January, March through May, October through December, with an average relative humidity of 78%, are most humid months in Umatac, Guam. The months with the highest humidity in Umatac are January, March through May, October through December, with an average relative humidity of 78%.
• Guam National Wildlife Refuge - December »
  With an average of 11h and 18min of daylight, December has the shortest days of the year in Guam National Wildlife Refuge. When is the sunrise / sunset in December in Guam National Wildlife Refuge?