September weather forecast
Sunrise Key, FL

The first month of the autumn, September, is still a warm month in Sunrise Key, Florida, with temperature in the range of an average high of 85.8°F (29.9°C) and an average low of 80.8°F (27.1°C).

Temperature

September's advent presents an average high-temperature of a warm 85.8°F (29.9°C), indicating a slight variation from the conditions of the previous month. The nights of September cool down to an average low of 80.8°F (27.1°C), subtly lower than daytime highs.

Heat index

For September, the heat index is estimated at a sweltering 96.8°F (36°C). Extra safeguards are necessary to prevent heat exhaustion and heat cramps. Prolonged activity might cause heatstroke.
Understanding the heat index involves considering values for shaded locales with light wind. The heat index could see an increase by 15 Fahrenheit (8 Celsius) degrees under direct sunshine.
Note: The heat index, also known as 'felt air temperature' or 'real feel', is an amalgamation of air temperature and humidity to express the equivalent perceived temperature. The individual's impression of temperature can be shaped by additional aspects such as metabolic variations, physical activity, and clothing. In the direct sunlight, the weather's impact can be amplified, possibly boosting the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
The human body keeps its cool primarily through perspiration, as this process enables sweat to evaporate, taking away the excess heat. When the air contains significant moisture, the efficiency of the evaporation process decreases, preventing the body from cooling down effectively and creating a feeling of overheating. When the body is unable to balance heat gain, its temperature elevates, which may induce thermal illnesses.

Humidity

In September, the average relative humidity is 73%.

Rainfall

In September, the rain falls for 23.6 days. Throughout September, 1.73" (44mm) of precipitation is accumulated. In Sunrise Key, during the entire year, the rain falls for 179 days and collects up to 15.55" (395mm) of precipitation.

Daylight

In Sunrise Key, the average length of the day in September is 12h and 18min.
On the first day of September, sunrise is at 7:00 am and sunset at 7:39 pm. On the last day of the month, sunrise is at 7:12 am and sunset at 7:07 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. A UV Index estimate of 6 to 7 represents a high threat to health from exposure to the Sun's UV rays for average individuals.
Note: In September, the maximum UV index of 7 suggests this advice:
Escape overexposure. People with light skin may incur burns in fewer than 20 minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage.