September weather forecast
Portsmouth, Dominica

Weather in September

September, the first month of the autumn in Portsmouth, is also a hot month, with an average temperature varying between 24°C (75.2°F) and 31°C (87.8°F).

Temperature

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

Rainfall

In Portsmouth, it is raining for 22 days, with typically 269mm (10.59") of accumulated precipitation. Throughout the year, there are 214 rainfall days, and 2252mm (88.66") of precipitation is accumulated.

Sea temperature

The month with the warmest seawater is September, with an average sea temperature of 29.4°C (84.9°F).
Note: For swimming, diving, and other water activities, temperatures between 25°C (77°F) and 29°C (84.2°F) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

Daylight

In Portsmouth, the average length of the day in September is 12h and 13min.
On the first day of September in Portsmouth, sunrise is at 05:53 and sunset at 18:18. On the last day of the month, sunrise is at 05:55 and sunset at 17:55 AST.

Sunshine

The average sunshine in September in Portsmouth is 7h.

UV index

March through September, with an average maximum UV index of 12, are months with the highest UV index. A UV Index estimate of 11, and higher, represents an ultimate health vulnerability from exposure to the Sun's UV radiation for average individuals.
Note: In September, the average maximum UV index of 12 translate into the following recommendations:
Practice all essential precautions. Protection against sun damage is crucial. 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. A broad-spectrum sunscreen of SPF 30+ should be liberally applied and re-applied every two hours, and immediately after an outdoor workout or a swim. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.
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FAQ

What is the warmest month in Portsmouth?

Warmest months in Portsmouth, Dominica, are June through September, with an average high-temperature of 31°C (87.8°F).

What is the temperature in September in Portsmouth?

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

How much does it rain in Portsmouth in September?

In Portsmouth, during September, the rain falls for 22 days and regularly aggregates up to 269mm (10.59") of precipitation.

What month is the sea warmest in Portsmouth?

September is the month with the warmest seawater in Portsmouth, with an average sea temperature of 29.4°C (84.9°F).

What is the water temperature in September in Portsmouth?

In September, the average sea temperature in Portsmouth is 29.4°C (84.9°F). For any water activity, surface water temperatures between 25°C (77°F) and 29°C (84.2°F) are considered as excellent and extremely pleasant for lengthened periods.

How many hours of daylight does Portsmouth have in September?

In Portsmouth, Dominica, the average day length in September is 12h and 13min.

When is the sunrise / sunset in September in Portsmouth?

On the first day of September in Portsmouth, sunrise is at 05:53 and sunset at 18:18. On the last day of the month, sunrise is at 05:55 and sunset at 17:55 AST.

How many hours of sunshine does Portsmouth have in September?

The average sunshine duration in September in Portsmouth, Dominica, is 7h.

What are the months with the highest UV index in Portsmouth?

March through September, with an average maximum UV index of 12, are months with the highest UV index.

How high is the UV index in September in Portsmouth?

The average daily maximum UV index in September is 12. A UV Index value of 11, and more, symbolizes an extreme health vulnerability from unprotected exposure to UV radiation.
Average rainfall days
Average sunshine
Average UV index

Average temperature in September
Portsmouth, Dominica

Average temperature in September - Portsmouth, Dominica
  • Average high temperature in September: 31°C

The warmest months (with the highest average high temperature) are June, July, August and September (31°C).
The month with the lowest average high temperature is January (28°C).

  • Average low temperature in September: 24°C

The months with the highest average low temperature are July, August and September (24°C).
The coldest months (with the lowest average low temperature) are January, February and March (21°C).

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Average rainfall in September
Portsmouth, Dominica

Average rainfall in September - Portsmouth, Dominica
  • Average rainfall in September: 269mm

The wettest month (with the highest rainfall) is November (300mm).
The driest month (with the least rainfall) is February (95mm).

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Average rainfall days in September
Portsmouth, Dominica

Average rainfall days in September - Portsmouth, Dominica
  • Average rainfall days in September: 22 days

The month with the highest number of rainy days is September (22 days).
The months with the least rainy days are February and April (14 days).

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Average sea temperature in September
Portsmouth, Dominica

Average sea temperature in September - Portsmouth, Dominica
  • Average sea temperature in September: 29.4°C

The best month for swimming (with the highest average sea temperature) is September (29.4°C).
The coldest month (with the lowest average sea temperature) is February (26.7°C).

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Average daylight in September /
Average sunshine in September
Portsmouth, Dominica

Average daylight in September / Average sunshine in September - Portsmouth, Dominica
  • Average daylight in September: 12h and 13min

The month with the longest days is June (Average daylight: 13h and 2min).
The month with the shortest days is December (Average daylight: 11h and 13min).

  • Average sunshine in September: 7h

The months with the most sunshine are March, April, May, June, July and August (Average sunshine: 8h).
The month with the least sunshine is December (Average sunshine: 6h).

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Average UV index in September
Portsmouth, Dominica

Average UV index in September - Portsmouth, Dominica
  • 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 8).

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