August weather forecastSanibel, FL

August
Weather in August
August's weather continues in the same vein as July’s, with high heat and substantial rainfall. Despite the formidable weather elements, Sanibel's August climate remains suited to outdoor activities, thanks to its significant daylight and sunshine hours. The city maintains regular weather patterns in August, with the highest daily average temperature standing at around 86.5°F (30.3°C). Concurrently, the month affords a good balance of light conditions, consisting of long daylight hours and significant sunshine moments. Even with the peak summer heat, Sanibel's August climate upholds the city's holiday appeal with its mild nights and enjoyable sea temperatures.Temperature
Sanibel's temperatures peak on average in August, reaching 88°F (31.1°C) at their highest and 81.1°F (27.3°C) at their lowest.Heat index
August's heat index is estimated at a sweltering 102.2°F (39°C). Apply extra caution, heat cramps and heat exhaustion could happen. Heatstroke might occur with long-duration activity.One should consider that heat index numbers are for shaded settings and light wind. With 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' or 'apparent temperature', gives an indication of how one might feel in terms of heat after considering humidity. The individual's experience of temperature can be shaped by numerous aspects such as metabolic variations, physical exertion, and attire. When you're directly under the sun's rays, remember that the heat index may surge by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly meaningful for babies and toddlers. Young kids are often more at risk than adults as they tend to perspire less. Besides, their skin surface is larger relative to their small bodies, and their increased heat output from their active lifestyle compounds their risk.
The human body keeps its cool primarily through perspiration, as this process enables sweat to evaporate, taking away the excess heat. An upsurge in relative humidity affects normal body cooling mechanisms by slowing evaporation, hence reducing the rate at which the body cools and intensifying the perception of heat. Rising body temperatures due to excess heat retention could signify impending heat disorders.
Humidity
March, May, July, August and October, with an average relative humidity of 73%, are the least humid months.Rainfall
The month with the most rainfall is August, when the rain falls for 27.3 days and typically aggregates up to 8.54" (217mm) of precipitation.Ocean temperature
August is the month with the warmest seawater, with an average ocean temperature of 87.1°F (30.6°C).Note: Water sports might not feel as refreshing in waters heated beyond 86°F (30°C).
Daylight
In Sanibel, Florida, the average length of the day in August is 13h and 2min.On the first day of August, sunrise is at 6:53 am and sunset at 8:15 pm. On the last day of the month, sunrise is at 7:07 am and sunset at 7:48 pm EDT.
Sunshine
In August, the average sunshine in Sanibel is 9.6h.UV index
The months with the highest UV index in Sanibel are May through September, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health risk from exposure to the Sun's UV rays for average individuals.Note: The maximum daily UV index, 7 in August, converts into the following recommendations:
Persist in precautions and follow sun safety policies. Keeping sunburn at bay is imperative. The hours from 10 a.m. to 4 p.m. have the most intense UV radiation. As much as possible, limit direct sun exposure during this period. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat. Caution! The Sun's UV rays become stronger due to reflections from water and sand.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in August
Sanibel, FL
- Average high temperature in August: 88°F
The warmest month (with the highest average high temperature) is August (88°F).
The month with the lowest average high temperature is January (69.8°F).
- Average low temperature in August: 81.1°F
The month with the highest average low temperature is August (81.1°F).
The coldest month (with the lowest average low temperature) is January (59.5°F).
Average pressure in August
Sanibel, FL
- Average pressure in August: 29.98"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is September (29.95"Hg).
Average wind speed in August
Sanibel, FL
- Average wind speed in August: 7.3mph
The windiest months (with the highest average wind speed) are October and November (10.1mph).
The calmest month (with the lowest average wind speed) is July (6.9mph).
Average humidity in August
Sanibel, FL
- Average humidity in August: 73%
The month with the highest relative humidity is December (77%).
The months with the lowest relative humidity are March, May, July, August and October (73%).
Average rainfall in August
Sanibel, FL
- Average rainfall in August: 8.54"
The wettest month (with the highest rainfall) is August (8.54").
The driest month (with the least rainfall) is February (1.06").
Average rainfall days in August
Sanibel, FL
- Average rainfall days in August: 27.3 days
The month with the highest number of rainy days is August (27.3 days).
The month with the least rainy days is February (8.2 days).
Average sea temperature in August
Sanibel, FL
- Average sea temperature in August: 87.1°F
The best month for swimming (with the highest average sea temperature) is August (87.1°F).
The coldest month (with the lowest average sea temperature) is January (65.3°F).
Average daylight in August /
Average sunshine in August
Sanibel, FL
- Average daylight in August: 13h and 0min
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 30min).
- Average sunshine in August: 9h and 36min
The month with the most sunshine is May (Average sunshine: 11h and 0min).
The month with the least sunshine is December (Average sunshine: 6h and 36min).
Average sunshine days in August
Sanibel, FL
- Average sunshine days in August: 2.3 days
The month with the most sunshine days is January (19.8 days).
The month with the least sunshine days is August (2.3 days).
Average UV index in August
Sanibel, FL
- Average UV index in August: 7
The months with the highest UV index are May, June, July, August and September (UV index 7).
The months with the lowest UV index are January and February (UV index 5).
Average cloud cover in August
Sanibel, FL
- Average cloud cover in August: 28
The month with the most cloud cover is January (Cloud cover 29).
The months with the least cloud cover are March and May (Cloud cover 23).
Average visibility in August
Sanibel, FL
- Average visibility in August: 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).





