September weather forecast and climate
Hagåtña, GU

September, the first month of the autumn, in Hagåtña, is still a warm month, with average temperature ranging between max 84.4°F (29.1°C) and min 82.8°F (28.2°C).

Temperature

In Hagåtña, the average high-temperature in September is relatively the same as in August - a still warm 84.4°F (29.1°C). In September, in Hagåtña, the average low-temperature is 82.8°F (28.2°C).

Heat index

In September, the average heat index is evaluated at a hot 93.9°F (34.4°C). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel', 'feels like', 'felt air temperature', or 'apparent temperature', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. This effect is individual, with diverse people perceiving weather differently for numerous reasons (metabolic differences, pregnancy, wind), and activity. Be aware that direct exposure to sunlight increases heat impact, and may raise the heat index additionally, by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.

Humidity

In Hagåtña, the average relative humidity is 77%.

Rainfall

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

Ocean temperature

In September, the average ocean temperature is 85.1°F (29.5°C).
Note: For any water activity, surface water temperatures between 77°F (25°C) and 84.2°F (29°C) are considered as excellent and extremely pleasant for lengthened periods.

Daylight

In Hagåtña, the average length of the day in September is 12.2h.

Sunshine

In Hagåtña, the average sunshine is 7.9h.

UV index

With an average maximum UV index of 6, September is the month with the lowest UV index. A UV Index reading of 6 to 7 represents a high health hazard from unprotected exposure to the Sun's UV rays for ordinary individuals.
Note: The daily maximum UV index of 6 in September interpret into the following advice:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.

What is the temperature in September in Hagåtña?

In Hagåtña, in September, the average high-temperature is 84.4°F (29.1°C), and the average low-temperature is 82.8°F (28.2°C). In September, the average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), that combines relative humidity and air temperature, is evaluated at 93.9°F (34.4°C).

What is the average humidity in September in Hagåtña?

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

How many days does it rain in September in Hagåtña?

In Hagåtña, Guam, during September, the rain falls for 28.1 days and regularly aggregates up to 10.28" (261mm) of precipitation.

What is the rainiest month in Hagåtña?

September is the month with the most rainfall in Hagåtña, Guam. Rain falls for 28.1 days and accumulates 10.28" (261mm) of precipitation.

What is the water temperature in September in Hagåtña?

In September, the average ocean temperature in Hagåtña, Guam, is 85.1°F (29.5°C). Water temperature between 77°F (25°C) and 84.2°F (29°C) is regarded as very warm and enjoyable by all. With these temperatures, water activities are pleasurable, without feeling uncomfortable for prolonged periods.

How many hours of daylight does Hagåtña have in September?

The average length of the day in September is 12.2h.

How many hours of sunshine does Hagåtña have in September?

In September, the average sunshine is 7.9h.

What is the month with the lowest UV index in Hagåtña?

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

How high is the UV index in September in Hagåtña?

The average daily maximum UV index in September in Hagåtña is 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from the exposure to the Sun's UV radiation.
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"

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

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%

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

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: 12.2h

The month with the longest days is June (Average daylight: 12.9h).
The month with the shortest days is December (Average daylight: 11.3h).

  • Average sunshine in September: 7.9h

The month with the most sunshine is June (Average sunshine: 10.6h).
The month with the least sunshine is November (Average sunshine: 6.3h).

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

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

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

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

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