September weather forecastUmatac, GU
September
Weather in September
September weather in Umatac, Guam juxtaposes elevated rainfall, peaking at 10.28" (261mm) alongside significantly reduced sunshine. This denotes a continuation of the rainy season, with rainfall being the most distinguishing feature, even when compared to August. Reduced daylight hours cast an overcast temperament over the city. The atmosphere compensates with soothing temperatures and moderated wind speeds. Still, the unwavering UV index does not relent, maintaining a consistent strength.Temperature
The transition into September shows a subtle variation to a still warm 84.4°F (29.1°C) from August's 84.7°F (29.3°C) in the average high-temperature. Nighttime temperatures during September report a consistent average of 82.8°F (28.2°C).Heat index
The heat index value for September is estimated at a tropical 93.2°F (34°C). Ensure additional precautions, heat exhaustion and heat cramps may be expected. Heatstroke could occur from sustained activity.It is essential to grasp that the heat index's numbers are for shade and light wind settings. The heat index can potentially augment by 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'real feel' or 'feels like', evaluates the perceived heat by adding the effect of moisture in the air. A person's impression of weather can be swayed by numerous aspects, among them metabolic variations, pregnancy, and activity levels. Being under direct sunshine can magnify the heat experience, possibly pushing up the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are primarily vital for children. Kids often lack the knowledge about the necessity to take breaks and consume liquids. Thirst, as a late symptom of dehydration, necessitates the maintenance of hydration, particularly during enduring physical activities.
Humidity
In Umatac, the average relative humidity in September is 77%.Rainfall
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.Daylight
In Umatac, the average length of the day in September is 12h and 13min.On the first day of September, sunrise is at 6:10 am and sunset at 6:32 pm. On the last day of the month, sunrise is at 6:10 am and sunset at 6:11 pm ChST.
Sunshine
In September, the average sunshine is 7.9h.UV index
September is the month with the lowest UV index, with an average maximum UV index of 6. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV rays for ordinary individuals.Note: A daily high UV index of 6 in September leads to these guidelines:
Take precautions against overexposure. Protection against sun damage is needed. Remember that the sun's UV radiation is strongest between 10 a.m. and 4 p.m. Make an effort to avoid direct sun exposure during these hours. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Umatac, 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
Umatac, 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
Umatac, 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
Umatac, 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
Umatac, 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
Umatac, 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
Umatac, GU
- Average daylight in September: 12h and 12min
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 24min).
- Average sunshine in September: 7h and 54min
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
Umatac, 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
Umatac, 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
Umatac, 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
Umatac, 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).
