August weather forecastHagåtña, GU
August
Weather in August
August rolls in promising hot days, but Hagåtña, Guam offers a pleasant surprise with its moderate tropical climate. Brace for generous rain showers, as this month sees the highest rainfall of the year, amounting to a staggering 9.76" (248mm) over 28.9 days. The city continues to teem with vibrant cultural events and breathtaking natural vistas that never fail to captivate the visiting population.Temperature
The months of July and August are noted for their peak temperatures, with an average high-temperature of 84.7°F (29.3°C).Heat index
During August, the heat index is appraised at a fiery hot 95°F (35°C). Additional precautions are required to avert heat cramps and heat exhaustion. Persistent activity may culminate in heatstroke.Regarding the heat index, one should be aware it's determined by shaded settings and mild winds. Exposure to unobstructed sunshine could lead to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'apparent temperature', is the outcome of merging air's temperature and its humidity metrics. This impact is subjective, influenced by the person's physical activity and individual heat perception, affected by factors including wind, attire, and metabolic differences. Be mindful that being in direct sunlight might mean feeling hotter, with the heat index rising by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are of high significance for children. Young children typically face greater hazards than adults because they do not sweat as much. Their larger skin surface in comparison to their little bodies and the high heat production from their active nature compounds their vulnerability.
One of the main methods the human body employs to cool down is by perspiring, as this process allows sweat to evaporate and remove excess heat. Elevated relative humidity diminishes evaporation, thereby reducing the body's ability to shed heat and creating a feeling of being too warm. As body temperatures escalate without effective heat release, one might face dehydration threats.
Humidity
August is the least humid month, with an average relative humidity of 76%.Rainfall
In Hagåtña, during August, the rain falls for 28.9 days and regularly aggregates up to 9.76" (248mm) of precipitation. In Hagåtña, during the entire year, the rain falls for 288.5 days and collects up to 60.08" (1526mm) of precipitation.Ocean temperature
August is the month with the warmest seawater, with an average ocean temperature of 85.5°F (29.7°C).Note: Swimming, diving, and other water endeavors at temperatures between 77°F (25°C) and 84.2°F (29°C) are considered enjoyable and satisfying for extended periods without discomfort.
Daylight
In August, the average length of the day is 12h and 34min.On the first day of August, sunrise is at 6:05 am and sunset at 6:48 pm. On the last day of the month, sunrise is at 6:09 am and sunset at 6:33 pm ChST.
Sunshine
In Hagåtña, the average sunshine in August is 7.6h.UV index
The months with the highest UV index are January through August, October through December, with an average maximum UV index of 7. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation for the ordinary person.Note: The maximum daily UV index of 7 in August interprets into the following recommendations:
Conform to measures and uphold sun safety traditions. Warding off skin and eye harm is necessary. The time between 10 a.m. and 4 p.m. is when UV radiation is at its peak. Limit exposure to direct sunlight during these hours. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Note! The Sun's UV radiation gets intensified with the reflection from sand and water.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in August
Hagåtña, GU
- Average high temperature in August: 84.7°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 August: 82.4°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 August
Hagåtña, GU
- Average pressure in August: 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 August
Hagåtña, GU
- Average wind speed in August: 9.6mph
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 August
Hagåtña, GU
- Average humidity in August: 76%
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 August
Hagåtña, GU
- Average rainfall in August: 9.76"
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 August
Hagåtña, GU
- Average rainfall days in August: 28.9 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 August
Hagåtña, GU
- Average sea temperature in August: 85.4°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 August /
Average sunshine in August
Hagåtña, GU
- Average daylight in August: 12h and 36min
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 August: 7h and 36min
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 August
Hagåtña, GU
- Average sunshine days in August: 1.6 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 August
Hagåtña, GU
- Average UV index in August: 7
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 August
Hagåtña, GU
- Average cloud cover in August: 46
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 August
Hagåtña, GU
- Average visibility in August: 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).





