September weather forecastLongboat Key, FL
September
Weather in September
September, the first month of the autumn in Longboat Key, is still a tropical month, with an average temperature ranging between min 77.4°F (25.2°C) and max 86.9°F (30.5°C).Temperature
During September, the average high-temperature is a still tropical 86.9°F (30.5°C), maintaining a close resemblance to that of the preceding month. Longboat Key, in September, observes a steady average low-temperature of 77.4°F (25.2°C).Heat index
Throughout September, the heat index is evaluated at a very hot 100.4°F (38°C). Ensure extra safety measures, heat exhaustion and heat cramps are likely. Continuous activity might result in heatstroke.When assessing, remember that heat index measurements are for light winds and shaded spots. The direct sun can potentially cause the heat index to increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. The influence of weather is personal, differing among individuals based on variations in body mass, stature, and the degree of physical exertion. Consider that direct sun exposure can intensify the felt heat, adding potentially 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are extremely significant for children. Youngsters are usually more at risk than adults, considering they sweat less. Additionally, their high skin surface area compared to their little bodies and their high heat production due to activity increases their risk.
The human body normally cools itself by perspiration, as evaporated sweat carries heat away from the body. Elevated relative humidity disrupts typical body cooling by reducing the evaporation rate, consequently decreasing the body's cooling rate and enhancing the feeling of heat. When body temperature rises due to excess heat gain beyond its removal capability, one might experience heat-related disorders.
Humidity
The average relative humidity in September is 75%.Rainfall
In Longboat Key, during September, the rain falls for 23.5 days and regularly aggregates up to 4.61" (117mm) of precipitation. In Longboat Key, during the entire year, the rain falls for 183.1 days and collects up to 34.92" (887mm) of precipitation.Ocean temperature
In Longboat Key, Florida, the average seawater temperature in September is 84.7°F (29.3°C).Note: Engaging in water activities, such as swimming or diving, in temperatures from 77°F (25°C) to 84.2°F (29°C) is very pleasurable for extended periods, without any discomfort.
Daylight
In September, the average length of the day is 12h and 19min.On the first day of the month, sunrise is at 7:10 am and sunset at 7:50 pm. On the last day of September, sunrise is at 7:23 am and sunset at 7:17 pm EDT.
Sunshine
In September, the average sunshine is 9h.UV index
The months with the highest UV index are May through September, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV radiation for average individuals.Note: The daily high UV index of 7 during September translates into the following recommendations:
Avert overexposure. Light-skinned people might experience burning in less than 20 minutes. Minimize exposure to direct sunlight and seek shade from 10 a.m. to 4 p.m., when UV radiation is most intense, but remember that shade structures may not offer complete protection. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days. Be wary! Reflections from sand and water make UV radiation more intense.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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).
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).
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).
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%).
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").
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).
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).
Average daylight in September /
Average sunshine in September
Longboat Key, FL
- Average daylight in September: 12h and 18min
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).
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).
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).
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).
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).
