September weather forecast
Saint John, VI

Beautiful scenery with green vegetation and the vast blue water around the islands in St John, Virgin Islands
Beautiful scenery with green vegetation and the vast blue water around the islands in St John, Virgin Islands

Weather in September

September, the first month of the autumn in Saint John, is also a hot month, with temperature in the range of an average low of 75.2°F (24°C) and an average high of 87.8°F (31°C).

Temperature

August and September, with an average high-temperature of 87.8°F (31°C), are the warmest months.

Rainfall

In Saint John, in September, it is raining for 16 days, with typically 5.63" (143mm) of accumulated precipitation. In Saint John, during the entire year, the rain falls for 156 days and collects up to 49.69" (1262mm) of precipitation.

Ocean temperature

The months with the warmest seawater in Saint John are September and October, with an average ocean temperature of 84.2°F (29°C).
Note: 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.

Daylight

In Saint John, the average length of the day in September is 12h and 14min.
On the first day of September in Saint John, sunrise is at 6:04 am and sunset at 6:33 pm. On the last day of the month, sunrise is at 6:09 am and sunset at 6:08 pm AST.

Sunshine

In September, the average sunshine is 8h.

UV index

March through September, with an average maximum UV index of 12, are months with the highest UV index in Saint John. A UV Index of 11, and more, symbolizes an excessive health risk from unsafe exposure to UV radiation for the average person.
Note: The average daily UV index of 12 in September transform into the following instructions:
Practice all-important precautions. Light skin people may get burned in less than 5 minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Even on cloudy days, a sunscreen with a minimum 30 sun protection factor should be generously applied and frequently re-applied, including after every swim or outdoor exercise. Caution! The reflection of sand and water significantly increases the intensity of the Sun's UV radiation.
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FAQ

What are the warmest months in Saint John?

Warmest months in Saint John are August and September, with an average high-temperature of 87.8°F (31°C).

What is the temperature in September in Saint John?

The average high-temperature, in September, in Saint John, United States Virgin Islands, is 87.8°F (31°C), while the average low-temperature is 75.2°F (24°C).

How much does it rain in Saint John in September?

In Saint John, United States Virgin Islands, during September, the rain falls for 16 days and regularly aggregates up to 5.63" (143mm) of precipitation.

What are the months with the warmest ocean in Saint John?

September and October, with an average ocean temperature of 84.2°F (29°C), are months with the warmest seawater.

What is the ocean temperature in September in Saint John?

In Saint John, United States Virgin Islands, in September, the average water temperature is 84.2°F (29°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 Saint John?

In September, the average day length is 12h and 14min.

When is the sunrise / sunset in September in Saint John?

On the first day of September, sunrise is at 6:04 am and sunset at 6:33 pm. On the last day of the month, sunrise is at 6:09 am and sunset at 6:08 pm AST.

How many hours of sunshine does Saint John have in September?

The average sunshine duration in September is 8h.

What is the month with the highest UV index in Saint John?

March through September, with an average maximum UV index of 12, are months with the highest UV index in Saint John, United States Virgin Islands.

What is the UV index intensity in September in Saint John?

In September, the average daily maximum UV index in Saint John, United States Virgin Islands, is 12. A UV Index of 11, and more, symbolizes an extreme health vulnerability from exposure to Sun's UV rays.
Average rainfall days
Average sunshine
Average UV index

Average temperature in September
Saint John, VI

Average temperature in September - Saint John, VI
  • Average high temperature in September: 88°F

The warmest months (with the highest average high temperature) are August and September (88°F).
The months with the lowest average high temperature are January, February, March and December (82°F).

  • Average low temperature in September: 75°F

The months with the highest average low temperature are June, July, August, September and October (75°F).
The coldest months (with the lowest average low temperature) are January, February and March (70°F).

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Average rainfall in September
Saint John, VI

Average rainfall in September - Saint John, VI
  • Average rainfall in September: 5.6"

The wettest months (with the highest rainfall) are October and November (6.3").
The driest month (with the least rainfall) is February (2.1").

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Average rainfall days in September
Saint John, VI

Average rainfall days in September - Saint John, VI
  • Average rainfall days in September: 16 days

The months with the highest number of rainy days are September and October (16 days).
The month with the least rainy days is April (9 days).

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Average sea temperature in September
Saint John, VI

Average sea temperature in September - Saint John, VI
  • Average sea temperature in September: 84°F

The best months for swimming (with the highest average sea temperature) are September and October (84°F).
The coldest months (with the lowest average sea temperature) are January, February, March and April (79°F).

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Average daylight in September /
Average sunshine in September
Saint John, VI

Average daylight in September / Average sunshine in September - Saint John, VI
  • Average daylight in September: 12h and 14min

The month with the longest days is June (Average daylight: 13h and 13min).
The month with the shortest days is December (Average daylight: 11h and 3min).

  • Average sunshine in September: 8h

The months with the most sunshine are March, April, July and August (Average sunshine: 9h).
The months with the least sunshine are November and December (Average sunshine: 7h).

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Average UV index in September
Saint John, VI

Average UV index in September - Saint John, VI
  • Average UV index in September: 12

The months with the highest UV index are March, April, May, June, July, August and September (UV index 12).
The month with the lowest UV index is December (UV index 7).

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