September weather forecast and climate
Naples, FL

Magnificent white sandy shores of Naples in Florida, USA, complete with a view of the city structure and plantation
Magnificent white sandy shores of Naples in Florida, USA, complete with a view of the city structure and plantation

Weather in September

The first month of the autumn, September, is still a tropical month in Naples, Florida, with temperature in the range of an average low of 78.4°F (25.8°C) and an average high of 87.1°F (30.6°C).

Temperature

In September, the average high-temperature is practically the same as in August - a still hot 87.1°F (30.6°C). In September, the average low-temperature is 78.4°F (25.8°C).

Heat index

The average heat index in September is evaluated at a sweltering 100.4°F (38°C). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Note that heat index values are valued for light wind and location in the shade. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like', 'real feel', 'felt air temperature', or 'apparent temperature', is a measure of how hot it feels when the actual air humidity is factored in. Additional factors like wind, clothing, metabolic differences, and activity influence one's weather impression. Be aware that direct exposure to sunlight increases heat impact and may raise the heat index 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.
To prevent overheating and help regulate its internal temperature, the human body sweat and rely on the evaporation to cool down. Under high air temperature and humidity (high heat index) conditions, perspiration is limited, and the perception of heat is increased. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

In Naples, the average relative humidity in September is 75%.

Rainfall

In Naples, in September, it is raining for 21.5 days, with typically 2.4" (61mm) of accumulated precipitation. In Naples, during the entire year, the rain falls for 162.1 days and collects up to 21.69" (551mm) of precipitation.

Ocean temperature

In September, the average ocean temperature in Naples is 85.6°F (29.8°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

In September, the average length of the day is 12.3h.

Sunshine

The average sunshine in September is 9.2h.

UV index

Months with the highest UV index in Naples, Florida, are May through September, with an average maximum UV index of 7. A UV Index reading of 6 to 7 represents a high health hazard from the exposure to the Sun's UV rays for the ordinary person.
Note: In September, the average maximum UV index of 7 translate into the following recommendations:
Take precautions against overexposure. Protection against sun damage is needed. 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. 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. Caution! The reflection of sand and water significantly increases the intensity of the Sun's UV radiation.
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FAQ

What is the temperature in September in Naples?

In September, in Naples, Florida, the average high-temperature is 87.1°F (30.6°C), and the average low-temperature is 78.4°F (25.8°C). The average heat index (a.k.a. 'feels like', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, in September is evaluated at 100.4°F (38°C).

What is the average humidity in September in Naples?

In September, the average relative humidity in Naples is 75%.

How much does it rain in Naples in September?

In Naples, Florida, during September, the rain falls for 21.5 days and regularly aggregates up to 2.4" (61mm) of precipitation.

What is the water temperature in September in Naples?

In September, the average ocean temperature in Naples is 85.6°F (29.8°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 Naples have in September?

The average length of the day in September is 12.3h.

How long on average sun shines in September in Naples?

In September, the average sunshine is 9.2h.

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

Months with the highest UV index in Naples are May through September, with an average maximum UV index of 7.

How high is the UV index in September in Naples?

The average daily maximum UV index in September in Naples, Florida, is 7. A UV Index estimate of 6 to 7 represents a high health vulnerability from the exposure to the Sun's UV rays.

Average temperature in September
Naples, FL

Average temperature in September - Naples, FL
  • Average high temperature in September: 87.1°F

The warmest month (with the highest average high temperature) is August (88.3°F).
The month with the lowest average high temperature is January (71.6°F).

  • Average low temperature in September: 78.4°F

The month with the highest average low temperature is August (80.2°F).
The coldest month (with the lowest average low temperature) is January (59.5°F).

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Average pressure in September
Naples, FL

Average pressure in September - Naples, FL
  • Average pressure in September: 29.94"

The month with the highest atmospheric pressure is January (30.11").
The month with the lowest atmospheric pressure is September (29.94").

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Average wind speed in September
Naples, FL

Average wind speed in September - Naples, FL
  • Average wind speed in September: 7mph

The windiest month (with the highest average wind speed) is November (9.2mph).
The calmest month (with the lowest average wind speed) is July (6.2mph).

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Average humidity in September
Naples, FL

Average humidity in September - Naples, FL
  • Average humidity in September: 75%

The month with the highest relative humidity is December (76%).
The month with the lowest relative humidity is March (72%).

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Average rainfall in September
Naples, FL

Average rainfall in September - Naples, FL
  • Average rainfall in September: 2.4"

The wettest month (with the highest rainfall) is August (4.29").
The driest month (with the least rainfall) is March (0.63").

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Average rainfall days in September
Naples, FL

Average rainfall days in September - Naples, FL
  • Average rainfall days in September: 21.5 days

The month with the highest number of rainy days is August (22.4 days).
The month with the least rainy days is February (7 days).

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Average sea temperature in September
Naples, FL

Average sea temperature in September - Naples, FL
  • Average sea temperature in September: 85.6°F

The best month for swimming (with the highest average sea temperature) is August (87.2°F).
The coldest month (with the lowest average sea temperature) is January (66.6°F).

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Average daylight in September /
Average sunshine in September
Naples, FL

Average daylight in September / Average sunshine in September - Naples, FL
  • Average daylight in September: 12.3h

The month with the longest days is June (Average daylight: 13.8h).
The month with the shortest days is December (Average daylight: 10.5h).

  • Average sunshine in September: 9.2h

Months with the most sunshine are May and July (Average sunshine: 11.1h).
The month with the least sunshine is December (Average sunshine: 6.7h).

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Average sunshine days in September
Naples, FL

Average sunshine days in September - Naples, FL
  • Average sunshine days in September: 7.1 days

The month with the most sunshine days is January (21.8 days).
The month with the least sunshine days is August (6.8 days).

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Average UV index in September
Naples, FL

Average UV index in September - Naples, FL
  • Average UV index in September: 7

Months with the highest UV index are May, June, July, August and September (UV index 7).
Months with the lowest UV index are January and February (UV index 5).

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Average cloud cover in September
Naples, FL

Average cloud cover in September - Naples, FL
  • Average cloud cover in September: 27

The month with the most cloud cover is January (Cloud cover 28).
Months with the least cloud cover are March and April (Cloud cover 22).

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Average visibility in September
Naples, FL

Average visibility in September - Naples, FL
  • 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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