September weather forecast
Port Saint John, FL

September, the first month of the autumn in Port Saint John, is still a hot month, with temperature in the range of an average high of 86.4°F (30.2°C) and an average low of 76.6°F (24.8°C).

Temperature

In September, Port Saint John experiences a barely noticeable shift in meteorological conditions, with average high-temperatures moving from 88.7°F (31.5°C) in August to a still hot 86.4°F (30.2°C). During September, Port Saint John's temperature falls to a steady low-temperature average of 76.6°F (24.8°C).

Heat index

In September, the average heat index is appraised at a fiery hot 100.4°F (38°C). Implement more safety precautions, heat cramps and heat exhaustion may happen. Persistent activity could induce heatstroke.
The heat index's values are generally associated with conditions in shade and light breezes. 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 'feels like' or 'real feel', is a fusion of air temperature and moisture levels to demonstrate the sensation of heat. The influence of weather is personal, differing among individuals based on variations in body mass, stature, and the degree of physical exertion. 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 hold particular significance for children. Children commonly overlook the importance of rest and fluid replenishment. Thirst, being a delayed sign of dehydration, emphasizes the need to keep hydration up, especially during lengthy physical activities.
The physiological response of the human body to excess warmth is to perspire, thereby cooling itself through sweat evaporation. Under conditions of high temperature and humidity (enhanced heat index), sweat production is compromised, exacerbating the sensation of warmth. As the body gains more heat than it can dissipate, there's a risk of increasing temperatures and resultant overheating.

Humidity

In Port Saint John, the average relative humidity in September is 78%.

Rainfall

In September, in Port Saint John, Florida, the rain falls for 23.8 days. Throughout September, 5.2" (132mm) of precipitation is accumulated. In Port Saint John, during the entire year, the rain falls for 202 days and collects up to 40.2" (1021mm) of precipitation.

Daylight

In Port Saint John, the average length of the day in September is 12h and 19min.
On the first day of the month, sunrise is at 7:01 am and sunset at 7:44 pm. On the last day of September, sunrise is at 7:15 am and sunset at 7:09 pm EDT.

Sunshine

The average sunshine in September in Port Saint John, Florida, is 8.9h.

UV index

The months with the highest UV index in Port Saint John, 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 exposure to the Sun's UV rays for ordinary individuals.
Note: A maximum daily UV index of 7 during September morphs into the following directions:
Steer clear of overexposure. Fair-skinned individuals can be scorched in less than 20 minutes. Stay in the shade and limit direct Sun exposure from 10 a.m. to 4 p.m., a time when UV radiation is particularly strong. Remember, however, that shade structures may not provide complete protection. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.