September weather forecast
Jacksonville, FL

As September comes around, Jacksonville experiences a gradual transition from summer towards fall. There is a noticeable drop in the sea temperature from 83.5°F (28.6°C) in August to 82.9°F (28.3°C). Despite the transition period, the vibrancy of Jacksonville's weather persists. The daylight hours gradually reduce, simplifying the shift towards the cozier latter months of the year. Nevertheless, the temperatures and relative humidity remain considerably high, still echoing summer resonance.

Temperature

Jacksonville's weather, upon September's arrival, documents an average high-temperature of a still hot 86.9°F (30.5°C), nearly identical to the prior month. Jacksonville, during the nights of September, experiences an average temperature drop to a warm 73.8°F (23.2°C).

Heat index

September's average heat index is evaluated at a sweltering 100.4°F (38°C). Preventive measures are required to mitigate the risk of heat cramps and heat exhaustion. Continuous activity may precipitate heatstroke.
Remember that heat index calculations are made for conditions in the shade with light wind. An exposure to direct sunlight may lift the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'feels like', is a calculation that merges air temperature and relative humidity to depict the sensation of warmth. A person's impression of weather can be shaped by several aspects, among them metabolic variations, pregnancy, and levels of physical activity. Being aware that direct sunlight can impact the felt heat might mean an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are largely significant for babies and toddlers. Kids frequently fail to realize the necessity for resting and hydrating. Thirst is an advanced indication of dehydration - hence, maintaining hydration, especially during extended physical activities, becomes essential.
Through perspiration, the body has a natural mechanism to eliminate excessive heat via sweat evaporation. A surge in relative humidity can disrupt the body's normal cooling function by slowing evaporation, hence reducing the rate at which the body cools and intensifying the perception of heat. Heat disorders may be on the horizon when body temperatures rise from inadequate heat management.

Humidity

In September, the average relative humidity is 75%.

Rainfall

In September, the rain falls for 18.5 days. Throughout September, 2.48" (63mm) of precipitation is accumulated. Throughout the year, there are 172.6 rainfall days, and 25.35" (644mm) of precipitation is accumulated.

Snowfall

In Jacksonville, snow does not fall in January through November.

Ocean temperature

In Jacksonville, Florida, in September, the average water temperature is 82.9°F (28.3°C).
Note: For swimming, diving, and various water activities, the temperatures ranging from 77°F (25°C) to 84.2°F (29°C) are seen as highly enjoyable and comfortable for extended durations without any discomfort.

Daylight

In Jacksonville, the average length of the day in September is 12h and 20min.
On the first day of the month, sunrise is at 7:03 am and sunset at 7:49 pm. On the last day of September, sunrise is at 7:19 am and sunset at 7:12 pm EDT.

Sunshine

The average sunshine in September is 8.5h.

UV index

The average daily maximum UV index in September in Jacksonville is 6. A UV Index value of 6 to 7 symbolizes a high health risk from exposure to the Sun's UV rays for the average person.
Note: The maximum daily UV index, 6 in September, converts into the following recommendations:
Incorporate safeguards and honour sun safety principles. Protection from skin and eye damage is obligatory. Between 10 a.m. and 4 p.m., the Sun emits the most powerful UV radiation. Limit direct exposure to the Sun during these hours. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized. Warning! The Sun's UV rays intensify with reflections from sand and water.