September weather forecast
Longboat Key, FL

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Weather in September

The first month of the autumn, September, is still a hot month in Longboat Key, Florida, with an average temperature ranging between max 86.9°F (30.5°C) and min 77.4°F (25.2°C).

Temperature

As Longboat Key steps into September, the average high-temperature is measured at a still tropical 86.9°F (30.5°C), displaying minor differences from August's 88.5°F (31.4°C). Longboat Key observes an average nighttime low-temperature of 77.4°F (25.2°C) during the month of September.

Heat index

September's heat index is estimated at a sweltering 100.4°F (38°C). Incorporate additional preventive steps, heat exhaustion and heat cramps are possible. Long-lasting activity may cause heatstroke.
Records show heat index calculations are tailored for shaded regions and mild winds. The heat index has the possibility to be enhanced by 15 Fahrenheit (8 Celsius) degrees when there is direct sun exposure.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is a measure that combines air temperature and relative humidity into a single value that indicates how hot the weather feels. The individual's impression of temperature can be affected by numerous factors such as metabolic variations, physical exertion, and attire. 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 hold particular significance for children. Children often miss understanding the importance of rest and rehydration. Thirst usually appears late during dehydration - therefore, maintaining hydration, particularly during long physical activities, is essential.
The body's natural response to excessive warmth is perspiration, as it allows for cooling through sweat evaporation. With high air temperature and humidity (high heat index) conditions, sweat production is restricted, leading to an amplified perception of heat. Accumulating more heat than the body can dissipate leads to an uptick in body temperature, with potential heat stress consequences.

Humidity

The average relative humidity in September in Longboat Key is 75%.

Rainfall

In Longboat Key, Florida, in September, during 23.5 rainfall days, 4.61" (117mm) of precipitation is typically accumulated. Throughout the year, in Longboat Key, there are 183.1 rainfall days, and 34.92" (887mm) of precipitation is accumulated.

Ocean temperature

In Longboat Key, in September, the average water temperature is 84.7°F (29.3°C).
Note: Water temperature ranging between 77°F (25°C) and 84.2°F (29°C) is considered very warm and pleasing for everyone. It allows for enjoyable water activities over extended periods without discomfort.

Daylight

The average length of the day in September is 12h and 19min.
On the first day of September, sunrise is at 7:10 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 7:17 pm EDT.

Sunshine

In September, the average sunshine is 9h.

UV index

May through September, with an average maximum UV index of 7, are months with the highest UV index in Longboat Key. A UV Index of 6 to 7 symbolizes a high threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: In September, a regular UV index of 7 translates into these guidelines:
Deflect overexposure. Sun protection is a necessity. To the best of your ability, limit your exposure to the sun between the hours of 10 a.m. and 4 p.m., when UV radiation is at its peak. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Attention! UV strength is notably upped by the reflection of sand and water.
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Frequently asked questions

Is it hot in Longboat Key during September?

The high-temperature, in September, in Longboat Key, records 86.9°F (30.5°C), while the low-temperature is 77.4°F (25.2°C). In September, the average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which calculates the temperature value influenced by the moisture in the air, is estimated at 100.4°F (38°C).

What is the average humidity in September in Longboat Key?

In September, the average relative humidity is 75%.

How much does it rain in Longboat Key in September?

In Longboat Key, Florida, in September, during 23.5 rainfall days, 4.61" (117mm) of precipitation is typically accumulated.

What is the water temperature in September in Longboat Key?

In September, the average ocean temperature in Longboat Key, Florida, is 84.7°F (29.3°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 Longboat Key?

In Longboat Key, the average day length in September is 12h and 19min.

When are sunrise and sunset in September in Longboat Key?

On the first day of September in Longboat Key, sunrise is at 7:10 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 7:17 pm EDT.

How many hours of sunshine does Longboat Key have in September?

In Longboat Key, the average sunshine duration in September is 9h.

What are the months with the highest UV index in Longboat Key?

May through September, with an average maximum UV index of 7, are months with the highest UV index in Longboat Key.

What is the UV index intensity in September in Longboat Key?

The average daily maximum UV index in September in Longboat Key is 7. A UV Index reading of 6 to 7 represents a high health vulnerability from exposure to Sun's UV rays.

Average temperature in September
Longboat Key, FL

Average temperature in September - Longboat Key, FL
  • Average high temperature in September: 86.9°F

The warmest month (with the highest average high temperature) is August (88.5°F).
The month with the lowest average high temperature is January (68.5°F).

  • Average low temperature in September: 77.4°F

The month with the highest average low temperature is August (79.7°F).
The coldest month (with the lowest average low temperature) is January (56.1°F).

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Average pressure in September
Longboat Key, FL

Average pressure in September - Longboat Key, FL
  • Average pressure in September: 29.95"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.95"Hg).

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Average wind speed in September
Longboat Key, FL

Average wind speed in September - Longboat Key, FL
  • Average wind speed in September: 7.2mph

The windiest month (with the highest average wind speed) is January (9.3mph).
The calmest month (with the lowest average wind speed) is July (6.4mph).

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Average humidity in September
Longboat Key, FL

Average humidity in September - Longboat Key, FL
  • Average humidity in September: 75%

The month with the highest relative humidity is December (76%).
The months with the lowest relative humidity are March, April and May (72%).

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Average rainfall in September
Longboat Key, FL

Average rainfall in September - Longboat Key, FL
  • Average rainfall in September: 4.61"

The wettest month (with the highest rainfall) is August (6.42").
The driest months (with the least rainfall) are February and November (1.06").

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Average rainfall days in September
Longboat Key, FL

Average rainfall days in September - Longboat Key, FL
  • Average rainfall days in September: 23.5 days

The month with the highest number of rainy days is August (26.8 days).
The months with the least rainy days are January, February and November (8.3 days).

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Average sea temperature in September
Longboat Key, FL

Average sea temperature in September - Longboat Key, FL
  • Average sea temperature in September: 84.8°F

The best month for swimming (with the highest average sea temperature) is August (86.7°F).
The coldest month (with the lowest average sea temperature) is January (64.1°F).

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Average daylight in September /
Average sunshine in September
Longboat Key, FL

Average daylight in September / Average sunshine in September - Longboat Key, FL
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 13h and 48min).
The month with the shortest days is December (Average daylight: 10h and 24min).

  • Average sunshine in September: 9h and 0min

The month with the most sunshine is May (Average sunshine: 11h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 30min).

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Average sunshine days in September
Longboat Key, FL

Average sunshine days in September - Longboat Key, FL
  • Average sunshine days in September: 4.5 days

The month with the most sunshine days is January (21.1 days).
The month with the least sunshine days is August (2.5 days).

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Average UV index in September
Longboat Key, FL

Average UV index in September - Longboat Key, FL
  • Average UV index in September: 7

The months with the highest UV index are May, June, July, August and September (UV index 7).
The month with the lowest UV index is January (UV index 4).

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Average cloud cover in September
Longboat Key, FL

Average cloud cover in September - Longboat Key, FL
  • Average cloud cover in September: 28

The months with the most cloud cover are January and December (Cloud cover 30).
The month with the least cloud cover is May (Cloud cover 22).

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Average visibility in September
Longboat Key, FL

Average visibility in September - Longboat Key, FL
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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Longboat Key, Florida, USA

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