August weather forecastUmatac, GU
August
Weather in August
Come August, Umatac, Guam endures its wettest episode with rainfall peaking at a high of 9.76" (248mm), slightly above what is recorded in July. The high rainfall makes this month a prominent part of the rainy season. However, the city's climate offsets the high precipitation with decreased wind speed. The cloud cover adds an element of serenity to the weather story of the month. Concurrently, the UV index remains steady, advocating for continual sun safety measures.Temperature
July and August, when the average high-temperature reaches 84.7°F (29.3°C), are the warmest months.Heat index
During August, the heat index is estimated at a sweltering 95°F (35°C). Implement additional safety measures to avoid heat cramps and heat exhaustion. Persistent activity might trigger heatstroke.One should consider that heat index numbers are for shaded settings and light wind. Direct sunlight can cause a surge in the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', melds the effects of warmth and moisture to generate a feeling of heat. Elements of metabolic variation, physical activity, and clothing contribute to the effect of temperature on an individual. Awareness is key; direct sunlight can enhance the weather's impact, possibly boosting the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular importance for children. Juveniles are regularly less conscious of the need to recuperate and rehydrate. Thirst is a tardy symptom of dehydration - hydration, especially during lengthy physical activities, should be maintained.
The human body has a built-in cooling mechanism through perspiration; evaporating sweat dissipates the excess heat. Greater relative humidity lessens the rate of evaporation, thus decreasing the body's heat dispersal, which gives rise to a sensation of overheating. Heat-related disorders may develop if heat gain in the body overshadows its cooling capacity, leading to elevated temperatures.
Humidity
The least humid month is August, with an average relative humidity of 76%.Rainfall
In Umatac, in August, it is raining for 28.9 days, with typically 9.76" (248mm) of accumulated precipitation. In Umatac, during the entire year, the rain falls for 288.5 days and collects up to 60.08" (1526mm) of precipitation.Daylight
In Umatac, the average length of the day in August is 12h and 34min.On the first day of the month, sunrise is at 6:06 am and sunset at 6:48 pm. On the last day of August, sunrise is at 6:09 am and sunset at 6:33 pm ChST.
Sunshine
The average sunshine in August is 7.6h.UV index
January through August, October through December, with an average maximum UV index of 7, are months with the highest UV index. A UV Index estimate of 6 to 7 represents a high health vulnerability from unsafe exposure to UV radiation for ordinary individuals.Note: A maximum high daily UV index of 7 during August translates into the following directions:
Take precautions and utilize sun safety practices. Protection against skin and eye damage is required. Limit direct sun exposure and seek shade between 10 a.m. and 4 p.m., the time of the most intense UV radiation, noting that shade structures may not provide total sun protection. 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 August
Umatac, 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
Umatac, 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
Umatac, 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
Umatac, 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
Umatac, 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
Umatac, 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 daylight in August /
Average sunshine in August
Umatac, 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 24min).
- 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
Umatac, 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
Umatac, 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
Umatac, 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
Umatac, 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).





