Naples
Florida, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Naples, FL

Magnificent aerial view of the white sandy shores of Naples in Florida, complete with a view of the city structure and plantation
Magnificent aerial view of the white sandy shores of Naples in Florida, complete with a view of the city structure and plantation
The first month of the autumn, September, is still a hot month in Naples, Florida, with temperature in the range of an average high of 87.1°F (30.6°C) and an average low of 78.4°F (25.8°C).

Temperature

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

Heat index

In September, the average heat index is estimated at a sweltering 100.4°F (38°C). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Take into consideration that the heat index values are calculated for shade and light wind conditions. With the exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel', 'apparent temperature', 'feels like', or 'felt air temperature', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. Additional factors like activity, clothing, metabolic differences, and pregnancy affect individual temperature impact. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
The human body cools itself through perspiration, as excessive warmth is removed from the body through sweat evaporation. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. If the body can not disperse the excessive heat and body temperature reaches conditions of hyperthermia, above 99.5°F (37.5°C) to 100.9°F (38.3°C), thermal conditions are potentially life-threatening.

Humidity

In Naples, Florida, the average relative humidity is 75%.

Rainfall

In Naples, 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 Naples, in September, the average water temperature is 85.6°F (29.8°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 Naples, Florida, is 12.3h.

Sunshine

The average sunshine in Naples is 9.2h.

UV index

May through September, with an average maximum UV index of 7, are months with the highest UV index in Naples. A UV Index reading of 6 to 7 represents a high health hazard from unsafe exposure to the UV radiation for ordinary individuals.
Note: The average daily UV index of 7 transform into the following instructions:
Take precautions against overexposure. Protection against sun damage is needed. 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. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.

What is the temperature in September in Naples?

The average high-temperature, in September, in Naples, is 87.1°F (30.6°C), while the average low-temperature is 78.4°F (25.8°C). The average heat index (a.k.a. 'felt air temperature', 'feels like'), that takes the relative humidity and factores it into the air temperature reading, in September is estimated at 100.4°F (38°C).

What is the average humidity in September in Naples?

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

How much does it rain in Naples in September?

In September, the rain falls for 21.5 days. Throughout September, 2.4" (61mm) of precipitation is accumulated.

How warm is the water in September in Naples?

In Naples, the average seawater temperature in September is 85.6°F (29.8°C). 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.

How many hours of daylight does Naples have in September?

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

How many hours of sunshine does Naples have in September?

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 are May through September, with an average maximum UV index of 7.

How high is the UV index in September in Naples?

In September, the average daily maximum UV index in Naples is 7. A UV Index estimate of 6 to 7 represents a high hazard to health from unprotected exposure to the UV radiation.
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).

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%).

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 lowest rainfall) is March (0.63").

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 lowest number of rainy days is February (7 days).

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).

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 shortest days is December (Average daylight: 10.5h).

  • Average sunshine in September: 9.2h

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

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).