September weather forecast
Fort Myers, FL

September witnesses the onset of fall, with a slight decrease in temperature, offering a respite from the summer. The rainfall levels retreat from their August high, indicating a slow transition toward drier months. The daylight hours begin reducing, signaling the end of long summer days. However, the city remains lively due to the pleasant sea temperature, the brightness of sunny hours, and vibrant surroundings. The humidity remains fairly constant, fostering a relatively comfortable environment.

Temperature

Fort Myers indicates an average high-temperature of a still tropical 87.6°F (30.9°C) in September, showing minor variation from August's 89.4°F (31.9°C). In Fort Myers, September is marked by an average low-temperature of 76.6°F (24.8°C).

Heat index

The heat index value during September is calculated to be a very hot 102.2°F (39°C). Ensure additional precautions, heat exhaustion and heat cramps may be expected. Heatstroke could occur from sustained activity.
Given the heat index, its values are aligned with shaded sites and gentle winds. Heat index values may rise by up to 15 Fahrenheit (8 Celsius) degrees when exposed to direct sunlight.
Note: The heat index, also known as 'real feel' or 'feels like', 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, with a diverse population experiencing it differently due to differences in body mass, stature, and degree of activity. One's exposure to direct sunlight has the potential to intensify the heat sensation, increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values remain especially vital for babies and toddlers. Young children are more at risk than adults since they tend to sweat less. Moreover, their large skin surface in proportion to their small bodies and the high heat production due to their activities contribute to their vulnerability.
Through perspiration, the body has a natural mechanism to eliminate excessive heat via sweat evaporation. When relative humidity is at high levels, the evaporation rate lessens, causing the body to keep more heat than it would in less humid conditions. Excessive heat that's not properly managed leads to increased body temperatures and resultant health issues.

Humidity

The months with the highest humidity in Fort Myers are September and December, with an average relative humidity of 76%.

Rainfall

In Fort Myers, during September, the rain falls for 20.9 days and regularly aggregates up to 2.95" (75mm) of precipitation. In Fort Myers, during the entire year, the rain falls for 159.2 days and collects up to 23.54" (598mm) of precipitation.

Ocean temperature

In Fort Myers, in September, the average water temperature is 84.2°F (29°C).
Note: For any water activity, surface water temperatures between 77°F (25°C) and 84.2°F (29°C) are considered as excellent and extremely pleasant for lengthened periods.

Daylight

The average length of the day in September is 12h and 18min.
On the first day of September, sunrise is at 7:07 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 7:14 pm EDT.

Sunshine

In Fort Myers, the average sunshine in September is 9.2h.

UV index

The months with the highest UV index are May through September, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV rays for ordinary individuals.
Note: The UV index of 7 in September translates into these instructions:
Refrain from overexposure. Fair-skinned individuals could burn in under 20 minutes. Between 10 a.m. and 4 p.m., the Sun's UV radiation is at its peak. Limit your exposure to direct sunlight during these hours. Employ a wide-brim hat for potent defense against up to 50% of UV rays. Heads up! The reflection of sand and water notably intensifies UV rays from the Sun.