September weather forecast
Dededo, GU

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Weather in September

In Dededo, September carries on the high precipitation trend from August, with rainfall peaking at 10.28" (261mm). A minor decrease in temperature occurs, shifting from 84.7°F (29.3°C) to 84.4°F (29.1°C). This month combines heavy showers with the vibrant tropical sun, creating an intriguing blend of weather conditions. The island's water forms, be it waterfalls or streams, teem with rainwater, creating mesmerizing natural spectacles. September showcases tropical island weather in its full glory, making it a memorable time for those who appreciate nature's unfiltered majesty.

Temperature

Dededo registers an average high-temperature of a still moderately hot 84.4°F (29.1°C) at the commencement of September, closely related to the preceding month. In Dededo, September is characterized by an average low-temperature of 82.8°F (28.2°C), indicating a minor drop from daytime highs.

Heat index

September's heat index is evaluated at a hot 93.2°F (34°C). Exercise increased caution, heat cramps and heat exhaustion are potential hazards. Continuous activity could lead to heatstroke.
It is worth noting that heat index values are gauged for conditions in the shade and light breezes. A rise of up to 15 Fahrenheit (8 Celsius) degrees in the heat index could result from direct sunlight.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is a value derived by merging air temperature with the humidity to convey how the climate feels. An individual's perception of weather can be influenced by a variety of factors including metabolic differences, being pregnant, and their degree of physical exertion. Direct sunlight can potentially raise the heat index by 15 Fahrenheit (8 Celsius) degrees, so it's crucial to consider. Heat index values are highly critical to babies and toddlers. Youngsters generally face more threats than adults given their lesser ability to sweat. Coupled with their larger skin surface relative to their small bodies and higher heat production due to their activities, they are more endangered.

Humidity

The average relative humidity in September is 77%.

Rainfall

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.

Daylight

In Dededo, the average length of the day in September is 12h and 13min.
On the first day of September, sunrise is at 6:09 am and sunset at 6:31 pm. On the last day of the month, sunrise is at 6:09 am and sunset at 6:11 pm ChST.

Sunshine

In September, the average sunshine is 7.9h.

UV index

The month with the lowest UV index is September, with an average maximum UV index of 6. A UV Index estimate of 6 to 7 represents a high threat to health from unsafe exposure to UV radiation for the ordinary person.
Note: An average UV index of 6 in September transforms into this advice:
Take precautions against overexposure. Fair-skinned people may get burned in less than 20 minutes. Attempt to stay under shade and limit exposure to the Sun between 10 a.m. and 4 p.m., when UV radiation is at its peak. Remember, devices such as parasols or canopies might not provide complete sun protection. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.
Updated: Aug 11, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is September?

Dededo in September has an average high-temperature of 84.4°F (29.1°C) and an average low-temperature of 82.8°F (28.2°C). In September, the average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which represents the influence of relative humidity on air temperature, is evaluated at 93.2°F (34°C).

What is the average humidity in September?

In Dededo, the average relative humidity in September is 77%.

What is the wettest month?

The month with the most rainfall is September, when the rain falls for 28.1 days and typically aggregates up to 10.28" (261mm) of precipitation.

How much does it rain in September?

In September, the rain falls for 28.1 days. Throughout September, 10.28" (261mm) of precipitation is accumulated.

What is the average length of the day in September?

In September, the average day length is 12h and 13min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:09 am and sunset at 6:31 pm. On the last day of the month, sunrise is at 6:09 am and sunset at 6:11 pm ChST.

How long on average sun shines in September?

In Dededo, the average sunshine duration in September is 7.9h.

What is the month with the lowest UV index?

September is the month with the lowest UV index, with an average maximum UV index of 6.

What is the UV index reading in September?

In September, the average daily maximum UV index is 6. A UV Index reading of 6 to 7 represents a high health vulnerability from exposure to Sun's UV rays.

Average temperature in September
Dededo, GU

Average temperature in September - Dededo, GU
  • Average high temperature in September: 84.4°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 September: 82.8°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).

Average pressure in September
Dededo, GU

Average pressure in September - Dededo, GU
  • Average pressure in September: 29.79"Hg

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

Average wind speed in September
Dededo, GU

Average wind speed in September - Dededo, GU
  • Average wind speed in September: 9.9mph

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).

Average humidity in September
Dededo, GU

Average humidity in September - Dededo, GU
  • Average humidity in September: 77%

The 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%).

Average rainfall in September
Dededo, GU

Average rainfall in September - Dededo, GU
  • Average rainfall in September: 10.28"

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

Average rainfall days in September
Dededo, GU

Average rainfall days in September - Dededo, GU
  • Average rainfall days in September: 28.1 days

The 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).

Average daylight in September /
Average sunshine in September
Dededo, GU

Average daylight in September / Average sunshine in September - Dededo, GU
  • Average daylight in September: 12h and 1min

The month with the longest days is June (Average daylight: 12h and 54min).
The month with the shortest days is December (Average daylight: 11h and 18min).

  • Average sunshine in September: 7h and 5min

The month with the most sunshine is June (Average sunshine: 10h and 36min).
The month with the least sunshine is November (Average sunshine: 6h and 18min).

Average sunshine days in September
Dededo, GU

Average sunshine days in September - Dededo, GU
  • Average sunshine days in September: 1.1 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).

Average UV index in September
Dededo, GU

Average UV index in September - Dededo, GU
  • Average UV index in September: 6

The 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).

Average cloud cover in September
Dededo, GU

Average cloud cover in September - Dededo, GU
  • Average cloud cover in September: 45

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

Average visibility in September
Dededo, GU

Average visibility in September - Dededo, GU
  • Average visibility in September: 6mi

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

Dededo, Guam, USA

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