September weather forecast
Saint John, VI

englishespañol中文
Share
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

Despite heading towards the tail end of summer, September in Saint John brings no reprieve from the warmth. The tropical maritime climate is at its zenith during this period, with plenty of sun-soaked days to enjoy. The high point featuring September weather is the substantial increase in rainfall, registering a notable 5.6" (142mm). Locals and visitors can expect an interplay of hot sunny days and refreshing evening showers.

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

Ocean temperature

September and October, with an average ocean temperature of 84.2°F (29°C), are months with the warmest seawater.
Note: For swimming, diving, and similar activities, the water temperatures between 77°F (25°C) and 84.2°F (29°C) are considered delightful, allowing for extended periods of enjoyment without discomfort.

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 the month, sunrise is at 6:04 am and sunset at 6:32 pm. On the last day of September, sunrise is at 6:09 am and sunset at 6:08 pm AST.

Sunshine

In Saint John, the average sunshine in September is 8h.

UV index

March through September, with an average maximum UV index of 12, are months with the highest UV index. A UV Index value of 11, and more, symbolizes an ultimate health vulnerability from unprotected exposure to Sun's UV rays for the average person.
Note: In September, the maximum UV index of 12 translates into these guidelines:
Take all required precautions, as unprotected skin and eyes can burn in minutes. Attempt to stay under shade and limit exposure to the Sun between 10 a.m. and 4 p.m., when UV radiation is at its peak. Remember, devices such as parasols or canopies might not provide complete sun protection. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance. Apply and frequently reapply a broad-spectrum SPF 30+ sunscreen after every two hours, or immediately after a swim or outdoor exercise. Stay aware! UV radiation is magnified when reflecting off sand and water.
[Resources]

Frequently asked questions

What is the warmest month in Saint John?

The highest point of temperatures falls in August and September, when the average high-temperature ascends to 87.8°F (31°C).

How hot is it in Saint John in September?

September temperatures in Saint John vary between a high-temperature of 87.8°F (31°C) and a low-temperature of 75.2°F (24°C).

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

In September, in Saint John, the rain falls for 16 days. Throughout September, 5.63" (143mm) of precipitation is accumulated.

What months are 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 in Saint John.

What is the ocean temperature in September in Saint John?

In Saint John, the average seawater temperature in September 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?

The average day length in September in Saint John is 12h and 14min.

When are sunrise and sunset in September in Saint John?

On the first day of September, sunrise is at 6:04 am and sunset at 6:32 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?

In Saint John, United States Virgin Islands, the average sunshine duration in September is 8h.

What are the months with the highest UV index in Saint John?

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

How high is the UV index 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 estimate of 11, and higher, represents an excessive health risk from unsafe exposure to Sun's UV rays.
Average rainfall days
Average daylight
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).

[Resources]

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").

[Resources]

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).

[Resources]

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).

[Resources]

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 1min

The month with the longest days is June (Average daylight: 13h and 12min).
The month with the shortest days is December (Average daylight: 11h and 6min).

  • 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).

[Resources]

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).

[Resources]

Saint John, United States Virgin Islands, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location