September weather forecastUpper Grand Lagoon, FL
September
Weather in September
September, the first month of the autumn in Upper Grand Lagoon, is also a moderately hot month, with temperature in the range of an average low of 74.7°F (23.7°C) and an average high of 85.5°F (29.7°C).Temperature
September's arrival brings an average high-temperature of a moderately hot 85.5°F (29.7°C), slightly deviating from August's 88.3°F (31.3°C). In Upper Grand Lagoon, September is marked by an average low-temperature of 74.7°F (23.7°C).Heat index
In September, the heat index is evaluated at a sweltering 95°F (35°C). Undertake enhanced precautions, heat exhaustion and heat cramps are possible risks. Continuous activity could trigger heatstroke.In the scope of the heat index, its values resonate with shade and light wind conditions. 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 'felt air temperature', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. The influence of weather is personal, differing among individuals based on variations in body mass, stature, and the degree of physical exertion. Given the impact of direct sunlight, it's noteworthy that the felt temperature can rise by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly important for children. Young individuals usually face more risks than adults due to their lower sweat production. Their large skin surface area relative to their tiny bodies and high heat production from their activities adds to their risk.
To cool down, the human body relies on perspiration, a process where excessive heat is eliminated as sweat evaporates. With a lot of moisture in the air, the evaporation process is not as effective, and the body does not cool down as efficiently, creating a perception of overheating. Increasing body temperatures can be a precursor to dehydration if the body can't shed the extra heat.
Humidity
In Upper Grand Lagoon, the average relative humidity in September is 74%.Rainfall
In Upper Grand Lagoon, in September, it is raining for 17.7 days, with typically 2.8" (71mm) of accumulated precipitation. Throughout the year, there are 166.1 rainfall days, and 35.83" (910mm) of precipitation is accumulated.Snowfall
In Upper Grand Lagoon, Florida, snow does not fall in February, April through December.Ocean temperature
In Upper Grand Lagoon, the average seawater temperature in September is 83.1°F (28.4°C).Note: Water temperatures from 77°F (25°C) to 84.2°F (29°C) make swimming, diving, and similar activities highly pleasurable and enjoyable for long periods without discomfort.
Daylight
In Upper Grand Lagoon, Florida, the average length of the day in September is 12h and 20min.On the first day of the month, sunrise is at 6:20 am and sunset at 7:05 pm. On the last day of September, sunrise is at 6:36 am and sunset at 6:29 pm CDT.
Sunshine
In September, the average sunshine is 9.3h.UV index
The average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV rays for the average person.Note: A maximum high UV index of 6 in September translates into the following recommendations:
Exercise precautions and adapt sun safety practices. Defence against skin and eye affliction is paramount. The Sun's UV radiation is at its strongest between the hours of 10 a.m. and 4 p.m. Minimize direct exposure to the sun during this period. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Heads up! The reflection of sand and water notably intensifies UV rays from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Upper Grand Lagoon, FL
- Average high temperature in September: 85.5°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 (60.1°F).
- Average low temperature in September: 74.7°F
The month with the highest average low temperature is July (78.6°F).
The coldest month (with the lowest average low temperature) is January (47.7°F).
Average pressure in September
Upper Grand Lagoon, FL
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.98"Hg).
Average wind speed in September
Upper Grand Lagoon, FL
- Average wind speed in September: 6.6mph
The windiest month (with the highest average wind speed) is January (9.2mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in September
Upper Grand Lagoon, FL
- Average humidity in September: 74%
The month with the highest relative humidity is December (77%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Upper Grand Lagoon, FL
- Average rainfall in September: 2.8"
The wettest month (with the highest rainfall) is August (5.04").
The driest month (with the least rainfall) is November (1.69").
Average rainfall days in September
Upper Grand Lagoon, FL
- Average rainfall days in September: 17.7 days
The month with the highest number of rainy days is August (23.8 days).
The month with the least rainy days is November (7.9 days).
Average snowfall days in September
Upper Grand Lagoon, FL
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and March (0.1 days).
The months with the least snowfall days are February, April, May, June, July, August, September, October, November and December (0 days).
Average sea temperature in September
Upper Grand Lagoon, FL
- Average sea temperature in September: 83.2°F
The best month for swimming (with the highest average sea temperature) is August (86°F).
The coldest month (with the lowest average sea temperature) is February (62.9°F).
Average daylight in September /
Average sunshine in September
Upper Grand Lagoon, FL
- Average daylight in September: 12h and 18min
The month with the longest days is June (Average daylight: 14h and 6min).
The month with the shortest days is December (Average daylight: 10h and 12min).
- Average sunshine in September: 9h and 18min
The months with the most sunshine are May and June (Average sunshine: 11h and 6min).
The month with the least sunshine is February (Average sunshine: 5h and 42min).
Average sunshine days in September
Upper Grand Lagoon, FL
- Average sunshine days in September: 10.4 days
The month with the most sunshine days is November (21 days).
The month with the least sunshine days is August (5.7 days).
Average UV index in September
Upper Grand Lagoon, FL
- Average UV index in September: 6
The months with the highest UV index are May, June, July and August (UV index 7).
The months with the lowest UV index are January, February and December (UV index 4).
Average cloud cover in September
Upper Grand Lagoon, FL
- Average cloud cover in September: 25
The month with the most cloud cover is December (Cloud cover 38).
The months with the least cloud cover are May and October (Cloud cover 22).
Average visibility in September
Upper Grand Lagoon, 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).





