September weather forecast
Siesta Key, FL

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

Temperature

The commencement of September brings an average high-temperature of a still hot 86.9°F (30.5°C), marking an inconsequential divergence from August. The low-temperature average for Siesta Key during September stands at a moderately hot 77.4°F (25.2°C).

Heat index

For September, the heat index is evaluated at a very hot 100.4°F (38°C). Incorporate extra safety measures to avoid heat exhaustion and heat cramps. Continuous activity could provoke heatstroke.
Remember that heat index calculations are made for conditions in the shade with light wind. The heat index may scale up by 15 Fahrenheit (8 Celsius) degrees with direct sun exposure.
Note: The heat index, also known as 'felt air temperature' or 'feels like', offers an insight into how hot it feels when we factor in moisture content. This effect is personal, shaped by the individual's physical activity and heat sensitivity, influenced by factors including wind, clothing, and metabolic variances. Keep in mind that direct sunshine exposure can amplify the weather's effects, possibly increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are primarily vital for children. Children frequently underestimate the importance of resting and drinking fluids. Thirst is a symptom of advanced dehydration - hence the need to hydrate regularly, especially during protracted physical exercises.
Perspiration is the body's default response to elevated temperatures, as it promotes the evaporation of sweat to achieve cooling. Increased relative humidity slows down evaporation, thereby decreasing the rate of heat removal from the body, culminating in a sensation of overheating. When heat gain exceeds the level the body can remove, body temperature begins to rise, and heat-related illnesses and disorders may develop.

Humidity

In September, the average relative humidity is 75%.

Rainfall

In Siesta Key, during September, the rain falls for 23.5 days and regularly aggregates up to 4.61" (117mm) of precipitation. In Siesta Key, Florida, during the entire year, the rain falls for 183.1 days and collects up to 34.92" (887mm) of precipitation.

Ocean temperature

In Siesta Key, in September, the average water temperature is 84.7°F (29.3°C).
Note: For engaging in water activities including swimming and diving, temperatures from 77°F (25°C) to 84.2°F (29°C) are perceived as perfect, providing pleasure for extended durations.

Daylight

In September, the average length of the day is 12h and 19min.
On the first day of the month, sunrise is at 7:09 am and sunset at 7:50 pm. On the last day of September, sunrise is at 7:22 am and sunset at 7:17 pm EDT.

Sunshine

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

UV index

The months with the highest UV index in Siesta Key, Florida, are May through September, with an average maximum UV index of 7. 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: The maximum daily UV index of 7 during September translates into the following directions:
Evade overexposure. Individuals with fair skin risk burning in under 20 minutes. Between 10 a.m. and 4 p.m., UV radiation is strongest. Make an effort to avoid direct sunlight during this time, remembering that shade structures may not provide full sun protection. To cut down UV radiation exposure by about half, sport a wide-brim hat. Warning! Sand and water reflections boost the intensity of UV exposure.