September weather forecast
Casselberry, FL

The first month of the autumn, September, is also a hot month in Casselberry, Florida, with an average temperature ranging between max 88.5°F (31.4°C) and min 74.3°F (23.5°C).

Temperature

The transition from August to September sees an average high-temperature of a still tropical 88.5°F (31.4°C), indicating a minor variance from the prior month. In Casselberry, the average nighttime temperature during September is a moderately hot 74.3°F (23.5°C).

Heat index

The heat index in September is computed to be a scorching 105.8°F (41°C). Special measures are necessary to avoid heat cramps and heat exhaustion. Persistent activity could result in heatstroke.
Note that heat index values are valued for light wind and location in the shade. Direct exposure to sunshine could lead to a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'real feel', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. Depending on the activity and the individual's heat perception, which may vary due to factors including wind, clothing, and metabolic variations, this effect remains subjective. Under direct sun rays, the felt temperature might be heightened, with the heat index increasing by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly important for children. Children usually face more risks than adults as their ability to sweat is less. Additionally, their larger skin surface in relation to their petite bodies and higher heat output due to their activities increases their vulnerability.
The body's inherent cooling system operates through perspiration, wherein evaporating sweat offsets excessive heat. An increase in relative humidity retards evaporation, subsequently reducing the body's heat removal rate and leading to a sensation of being overly warm. Should the body fail to balance its heat gain, the escalating temperature poses health challenges.

Humidity

With an average relative humidity of 77%, September is the most humid month in Casselberry.

Rainfall

In Casselberry, Florida, during September, the rain falls for 19.7 days and regularly aggregates up to 2.48" (63mm) of precipitation. In Casselberry, during the entire year, the rain falls for 172.9 days and collects up to 22.76" (578mm) of precipitation.

Daylight

In September, the average length of the day is 12h and 19min.
On the first day of September in Casselberry, sunrise is at 7:03 am and sunset at 7:46 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 7:11 pm EDT.

Sunshine

In Casselberry, Florida, the average sunshine in September is 8.8h.

UV index

The months with the highest UV index in Casselberry are May through September, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: A maximum UV index of 7 in September translates into the following recommendations:
Beware of overexposure. Fair-skinned individuals risk burning in less than 20 minutes. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a time when UV radiation is at its strongest, and remember that parasols or canopies do not offer full protection. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses.