September weather forecast and climate
Charlotte Amalie, VI

The Charlotte Amalie Harbour within the United States Virgin Islands
The Charlotte Amalie Harbour within the United States Virgin Islands

Weather in September

September, the first month of the autumn, in Charlotte Amalie, is also a moderately hot month, with average temperature fluctuating between 81.3°F (27.4°C) and 84°F (28.9°C).

Temperature

The warmest month is September, with an average high-temperature of 84°F (28.9°C) and an average low-temperature of 81.3°F (27.4°C).

Heat index

In September, the average heat index is appraised at a hot 92.8°F (33.8°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', 'felt air temperature', 'feels like', 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 subjective, depending on the activity and individual's heat perception influenced by various reasons (clothing, pregnancy, differences in body mass, height, and shape). 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 September, the average relative humidity is 77%.

Rainfall

The month with the most rainfall is September when the rain falls for 22.2 days and typically aggregates up to 4.45" (113mm) of precipitation.

Ocean temperature

The month with the warmest seawater in Charlotte Amalie is September, with an average ocean temperature of 84.9°F (29.4°C).
Note: 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.

Daylight

The average length of the day is 12.2h.

Sunshine

The average sunshine in September is 8.7h.

UV index

January through December, with an average maximum UV index of 7, are months with the highest UV index. January through December, with an average maximum UV index of 7, are months with the lowest UV index in Charlotte Amalie. A UV Index estimate of 6 to 7 represents a high health vulnerability from the exposure to the Sun's UV rays for ordinary individuals.
Note: The average daily UV index of 7 in September transform into the following instructions:
Take precautions and utilize sun safety practices. Protection against the skin and eye damage is required. 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 strength of the UV rays is significantly increased by the reflection of the water and sand.
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FAQ

What is the warmest month in Charlotte Amalie?

September is the warmest month in Charlotte Amalie, with an average high-temperature of 84°F (28.9°C) and an average low-temperature of 81.3°F (27.4°C).

What is the temperature in September in Charlotte Amalie?

In Charlotte Amalie, United States Virgin Islands, in September, the average high-temperature is 84°F (28.9°C), and the average low-temperature is 81.3°F (27.4°C). In September, the average heat index (a.k.a. 'felt air temperature', 'feels like'), that combines relative humidity and air temperature, is calculated to 92.8°F (33.8°C).

What is the average humidity in September in Charlotte Amalie?

In Charlotte Amalie, United States Virgin Islands, the average relative humidity in September is 77%.

How much does it rain in Charlotte Amalie in September?

In Charlotte Amalie, in September, it is raining for 22.2 days, with typically 4.45" (113mm) of accumulated precipitation.

What is the wettest month in Charlotte Amalie?

The month with the most rainfall is September when the rain falls for 22.2 days and typically aggregates up to 4.45" (113mm) of precipitation.

What is the month with the warmest ocean in Charlotte Amalie?

September is the month with the warmest seawater in Charlotte Amalie, United States Virgin Islands, with an average ocean temperature of 84.9°F (29.4°C).

How warm is the water in September in Charlotte Amalie?

In Charlotte Amalie, United States Virgin Islands, the average seawater temperature in September is 84.9°F (29.4°C). For swimming, diving, and other water activities, temperatures between 77°F (25°C) and 84.2°F (29°C) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

What is the average length of the day in September in Charlotte Amalie?

In Charlotte Amalie, United States Virgin Islands, the average length of the day in September is 12.2h.

How long on average sun shines in September in Charlotte Amalie?

In Charlotte Amalie, the average sunshine in September is 8.7h.

When is the highest UV index in Charlotte Amalie?

January through December, with an average maximum UV index of 7, are months with the highest UV index.

What is the month with the lowest UV index in Charlotte Amalie?

Months with the lowest UV index in Charlotte Amalie are January through December, with an average maximum UV index of 7.

How high is the UV index in September in Charlotte Amalie?

In September, the average daily maximum UV index is 7. A UV Index reading of 6 to 7 represents a high health vulnerability from unprotected exposure to the UV radiation.

Average temperature in September
Charlotte Amalie, VI

Average temperature in September - Charlotte Amalie, VI
  • Average high temperature in September: 84°F

The warmest month (with the highest average high temperature) is September (84°F).
The month with the lowest average high temperature is March (78.4°F).

  • Average low temperature in September: 81.3°F

The month with the highest average low temperature is October (81.5°F).
The coldest month (with the lowest average low temperature) is March (75.7°F).

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Average pressure in September
Charlotte Amalie, VI

Average pressure in September - Charlotte Amalie, VI
  • Average pressure in September: 29.93"

Months with the highest atmospheric pressure are January and February (30.02").
Months with the lowest atmospheric pressure are October and November (29.91").

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Average wind speed in September
Charlotte Amalie, VI

Average wind speed in September - Charlotte Amalie, VI
  • Average wind speed in September: 11.7mph

The windiest month (with the highest average wind speed) is July (15mph).
The calmest month (with the lowest average wind speed) is October (11.1mph).

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Average humidity in September
Charlotte Amalie, VI

Average humidity in September - Charlotte Amalie, VI
  • Average humidity in September: 77%

Months with the highest relative humidity are May, June, July and August (78%).
Months with the lowest relative humidity are January, February, March, October, November and December (75%).

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Average rainfall in September
Charlotte Amalie, VI

Average rainfall in September - Charlotte Amalie, VI
  • Average rainfall in September: 4.45"

The wettest month (with the highest rainfall) is September (4.45").
The driest month (with the least rainfall) is February (1.22").

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Average rainfall days in September
Charlotte Amalie, VI

Average rainfall days in September - Charlotte Amalie, VI
  • Average rainfall days in September: 22.2 days

The month with the highest number of rainy days is November (25.5 days).
Months with the least rainy days are February, March and June (18.2 days).

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Average sea temperature in September
Charlotte Amalie, VI

Average sea temperature in September - Charlotte Amalie, VI
  • Average sea temperature in September: 85°F

The best month for swimming (with the highest average sea temperature) is September (85°F).
The coldest month (with the lowest average sea temperature) is February (78.7°F).

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Average daylight in September /
Average sunshine in September
Charlotte Amalie, VI

Average daylight in September / Average sunshine in September - Charlotte Amalie, VI
  • Average daylight in September: 12.2h

The month with the longest days is June (Average daylight: 13.2h).
The month with the shortest days is December (Average daylight: 11h).

  • Average sunshine in September: 8.7h

The month with the most sunshine is June (Average sunshine: 10.5h).
Months with the least sunshine are November and December (Average sunshine: 6.5).

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Average sunshine days in September
Charlotte Amalie, VI

Average sunshine days in September - Charlotte Amalie, VI
  • Average sunshine days in September: 5.2 days

Months with the most sunshine days are March and April (7.3 days).
The month with the least sunshine days is November (2.4 days).

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Average UV index in September
Charlotte Amalie, VI

Average UV index in September - Charlotte Amalie, VI
  • Average UV index in September: 7

Months with the highest UV index are January, February, March, April, May, June, July, August, September, October, November and December (UV index 7).
Months with the lowest UV index are January, February, March, April, May, June, July, August, September, October, November and December (UV index 7).

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Average cloud cover in September
Charlotte Amalie, VI

Average cloud cover in September - Charlotte Amalie, VI
  • Average cloud cover in September: 36

Months with the most cloud cover are May and July (Cloud cover 40).
The month with the least cloud cover is February (Cloud cover 33).

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Average visibility in September
Charlotte Amalie, VI

Average visibility in September - Charlotte Amalie, VI
  • 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).

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