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 still a hot month, with an average temperature ranging between min 75.2°F (24°C) and max 87.8°F (31°C).

Temperature

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

Rainfall

In Saint John, in September, it is raining for 16 days, with typically 5.63" (143mm) of accumulated precipitation. Throughout the year, in Saint John, there are 156 rainfall days, and 49.69" (1262mm) of precipitation is accumulated.

Ocean temperature

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

The average length of the day in September in Saint John, United States Virgin Islands, is 12h and 14min.
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.

Sunshine

The average sunshine in September is 8h.

UV index

The months with the highest UV index are March through September, with an average maximum UV index of 12. A UV Index estimate of 11, and higher, represents an ultimate health vulnerability from exposure to the Sun's UV rays for average individuals.
Note: The average daily UV index of 12 in September transform into the following instructions:
Take all required precautions, as unprotected skin and eyes can burn in minutes. 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. 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. 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?

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

What is the temperature in September in Saint John?

The average high-temperature, in September, is 87.8°F (31°C), while the average low-temperature is 75.2°F (24°C).

How many days does it rain in September in Saint John?

In Saint John, in September, during 16 rainfall days, 5.63" (143mm) of precipitation is typically accumulated.

When is the ocean warmest in Saint John?

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

How warm is the water 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 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.

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

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

What time are sunrise and sunset in September in Saint John?

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

How long on average sun shines in September in Saint John?

In Saint John, United States Virgin Islands, 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.

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

In Saint John, the average daily maximum UV index in September is 12. A UV Index reading of 11, and higher, represents an excessive health risk 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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