September weather forecastHagåtña, GU
September
Weather in September
September in Hagåtña, Guam, delivers yet another month of moderate tropical weather marked by hot days and cool nights. This is an ideal period for visitors looking to immerse in the local traditions and community gatherings. Expect frequent rains, with a total accumulated precipitation of 10.28" (261mm) falling over 28.1 days. The consistency of the weather, combined with the allure of various festivals, gives September a charm of its own.Temperature
September denotes a minimal variation in the average high-temperature to a still moderately hot 84.4°F (29.1°C) from August's 84.7°F (29.3°C). September's average low-temperature is a still warm 82.8°F (28.2°C), reflecting a minor difference from the day's peak temperatures.Heat index
The heat index in September is appraised at a hot 93.2°F (34°C). Adopt enhanced safety measures, heat exhaustion and heat cramps could occur. Continuous activity may induce heatstroke.Understanding the heat index involves considering values for shaded locales with light wind. When under direct sunshine, the heat index may be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'real feel', gives a temperature feeling by integrating air temperature and humidity. The influence of weather is personal, with varied individuals experiencing it differently due to differences in body mass, stature, and physical exertion levels. Direct sun exposure is noteworthy in its ability to escalate the felt temperature, potentially adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are particularly important for children. Children commonly overlook the importance of rest and fluid replenishment. Thirst, being a delayed sign of dehydration, emphasizes the need to keep hydration up, especially during lengthy physical activities.
Humidity
In Hagåtña, the average relative humidity in September is 77%.Rainfall
September is the month with the most rainfall. Rain falls for 28.1 days and accumulates 10.28" (261mm) of precipitation.Ocean temperature
In Hagåtña, the average seawater temperature in September is 85.1°F (29.5°C).Note: Temperatures between 77°F (25°C) and 84.2°F (29°C) in water are ideal for swimming, diving, and other activities, providing enjoyment and comfort for extended durations.
Daylight
The average length of the day in September is 12h and 13min.On the first day of the month, sunrise is at 6:09 am and sunset at 6:32 pm. On the last day of September, in Hagåtña, sunrise is at 6:10 am and sunset at 6:11 pm ChST.
Sunshine
The average sunshine in September 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 threat to health from unsafe exposure to UV radiation for the ordinary person.Note: A daily maximum UV index of 6 in September translates into the following instructions:
Use protective steps and abide by sun safety guidelines. Safeguarding against skin and eye harm is necessary. To the best of your ability, limit your exposure to the sun between the hours of 10 a.m. and 4 p.m., when UV radiation is at its peak. Opt for tightly woven and loose clothing to enhance protection from the Sun. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Hagåtña, 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
Hagåtña, 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
Hagåtña, 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
Hagåtña, 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
Hagåtña, 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
Hagåtña, 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 sea temperature in September
Hagåtña, GU
- Average sea temperature in September: 85°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).
Average daylight in September /
Average sunshine in September
Hagåtña, 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 18min).
- 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
Hagåtña, 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
Hagåtña, 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
Hagåtña, 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
Hagåtña, 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).
