September weather forecast
Myrtle Island, FL

The first month of the autumn, September, is also a hot month in Myrtle Island, Florida, with temperature in the range of an average low of 73.4°F (23°C) and an average high of 88.7°F (31.5°C).

Temperature

Myrtle Island marks the start of September with an average high-temperature of a still tropical 88.7°F (31.5°C), hinting at a slight fluctuation from August's 92.3°F (33.5°C). Throughout the month of September, Myrtle Island expects an average low of 73.4°F (23°C).

Heat index

For September, the heat index is calculated to be a scorching 105.8°F (41°C). Exercise enhanced safety steps, heat cramps and heat exhaustion are probable. Heatstroke could be a result of sustained activity.
Know that the heat index computations account for shaded terrains and slight winds. The direct sun can potentially cause the heat index to increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', comes about by integrating the temperature readings with the humidity levels. The individual's impression of temperature can be affected by numerous factors such as metabolic variations, physical exertion, and attire. When in direct sunlight, one should be cautious as it can raise the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly important for children. Young individuals usually face greater risks than adults as their sweat production is less. Also, their larger skin surface relative to their small bodies and the high heat generation due to their activity contributes to their vulnerability.
Evaporation of sweat is the main factor behind the cooling effect of perspiration in the human body. With higher relative humidity, the rate of evaporation is reduced, resulting in increased heat retention in the body compared to drier air. When body heat isn't effectively managed, risks of dehydration and overheating amplify.

Humidity

July through September, with an average relative humidity of 77%, are the most humid months in Myrtle Island.

Rainfall

In Myrtle Island, during September, the rain falls for 15.7 days and regularly aggregates up to 1.85" (47mm) of precipitation. Throughout the year, in Myrtle Island, there are 151.1 rainfall days, and 17.99" (457mm) of precipitation is accumulated.

Daylight

In Myrtle Island, the average length of the day in September is 12h and 20min.
On the first day of September, sunrise is at 7:03 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 7:12 pm EDT.

Sunshine

The average sunshine in September is 8.1h.

UV index

In Myrtle Island, the average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: The maximum UV index of 6 during September leads to these instructions:
Take precautions and utilize sun safety practices. Protection against skin and eye damage is required. Seek shade and limit direct Sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its peak, but be aware that not all shade structures provide complete sun protection. During bright days, sunglasses that offer UVA and UVB defense are recommended.