September weather forecast
Guam, USA

September in Guam is emblematic of the late stages of the wet season. During this month, temperatures usually range from 82°F (27.8°C) to 89°F (31.7°C). The frequent downpours and high humidity levels still dominate, though the month serves as a gradual bridge to the eventual decline of the monsoon's intensity.

Every corner of Guam is influenced by September's pronounced rainfall. The landscapes, which have been consistently soaked throughout the past few months, maintain their lush and vibrant appearance. While the intensity of the rains remains high, September often begins to show subtle signs of a shift towards the concluding phase of the wet season.

Rain remains a staple of September, but its frequency and intensity can start to taper off slightly compared to the peak wet months of July and August. The dependable northeast trade winds, with velocities from 10mph (16.1km/h) to 20mph (32.2km/h), endure in their role, delivering periodic refreshing breaks from the prevailing moisture and warmth.

The ocean waters around Guam, while still warm, can exhibit increased choppiness due to the prolonged wet conditions and occasional storm activities. Such dynamics necessitate heightened awareness for those indulging in marine ventures. As September fades, October ushers in the waning moments of the wet season, with the climate starting to hint at the impending drier months.

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• Hagåtña - September »
  In Hagåtña, Guam, during September, the rain falls for 28.1 days and regularly aggregates up to 10.28" (261mm) of precipitation. September in Hagåtña delivers yet another month of moderate tropical weather marked by hot days and cool nights.
• Dededo - September »
  The month with the most rainfall in Dededo is September, when the rain falls for 28.1 days and typically aggregates up to 10.28" (261mm) of precipitation. In Dededo in September, during 28.1 rainfall days, 10.28" (261mm) of precipitation is typically accumulated.
• Santa Rita - September »
  Santa Rita transitions into September recording an average high-temperature of a still warm 84.4°F (29.1°C), closely aligning with the preceding month's temperature. In Santa Rita, the month of September brings a consistent average low-temperature of 82.8°F (28.2°C), slightly cooler than its daytime highs.
• Agat - September »
  September is the month with the lowest UV index in Agat with an average maximum UV index of 6. Agat's September average high-temperature settles at a still moderately hot 84.4°F (29.1°C), showing a near match with the preceding month.
• Piti - September »
  The month with the most rainfall in Piti, Guam, is September, when the rain falls for 28.1 days and typically aggregates up to 10.28" (261mm) of precipitation. September is the month with the lowest UV index in Piti, Guam, with an average maximum UV index of 6.
• Talofofo - September »
  Steady UV levels and visibility indicate clear, sunny autumn days, making September a vital transition month for Talofofo's weather. The month with the lowest UV index in Talofofo is September, with an average maximum UV index of 6.
• Inarajan - September »
  The month with the most rainfall in Inarajan is September, when the rain falls for 28.1 days and typically aggregates up to 10.28" (261mm) of precipitation. In Inarajan during September, the rain falls for 28.1 days and regularly aggregates up to 10.28" (261mm) of precipitation.
• Merizo - September »
  The month with the most rainfall in Merizo is September, when the rain falls for 28.1 days and typically aggregates up to 10.28" (261mm) of precipitation. The month with the most rainfall in Merizo is September, when the rain falls for 28.1 days and typically aggregates up to 10.28" (261mm) of precipitation.
• Umatac - September »
  The month with the most rainfall in Umatac is September, when the rain falls for 28.1 days and typically aggregates up to 10.28" (261mm) of precipitation. The month with the most rainfall in Umatac is September, when the rain falls for 28.1 days and typically aggregates up to 10.28" (261mm) of precipitation.
• Guam National Wildlife Refuge - September »
  On the first day of September in Guam National Wildlife Refuge, sunrise is at 6:09 am and sunset at 6:32 pm. On the first day of September in Guam National Wildlife Refuge, Guam, sunrise is at 6:09 am and sunset at 6:32 pm.