September weather forecast
Surfside, FL

September, the first month of the autumn in Surfside, is still a hot month, with an average temperature varying between 80.6°F (27°C) and 86.4°F (30.2°C).

Temperature

September observes an average high-temperature of a still tropical 86.4°F (30.2°C), marking an insignificant difference from August's 88°F (31.1°C). September nights witness a slight temperature decrease, averaging at a warm 80.6°F (27°C).

Heat index

Throughout September, the heat index is calculated to be a fiery hot 96.8°F (36°C). Adopt heightened safety measures, heat cramps and heat exhaustion may occur. Sustained activity might cause heatstroke.
One should consider that heat index numbers are for shaded settings and light wind. The heat index could experience an increase of 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is an aggregate value of air's warmth and moisture to show the human-felt temperature. The impact of weather on an individual can be subjective, affected by the person's activity and heat perception, which can vary due to elements including wind, clothing, and metabolic differences. Given direct exposure to sunlight, one might experience a rise in the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Children frequently underestimate the importance of resting and drinking fluids. Thirst is a symptom of advanced dehydration - hence the need to hydrate regularly, especially during protracted physical exercises.
When faced with excessive heat, the human body begins to perspire, utilizing the cooling benefits of sweat evaporation. In the presence of elevated relative humidity, the evaporation rate decreases. This reduction leads to increased body heat retention compared to conditions of dry air. When body temperature rises due to an imbalance in heat gain, there's a potential for dehydration and overheating.

Humidity

In September, the average relative humidity in Surfside is 73%.

Rainfall

In Surfside, in September, during 21.3 rainfall days, 1.34" (34mm) of precipitation is typically accumulated. In Surfside, Florida, during the entire year, the rain falls for 166.7 days and collects up to 12.91" (328mm) of precipitation.

Ocean temperature

In Surfside, in September, the average water temperature is 85.5°F (29.7°C).
Note: Surface water temperatures between 77°F (25°C) and 84.2°F (29°C) offer outstanding conditions for any water activity, providing extreme pleasure for extended periods.

Daylight

The average length of the day in September in Surfside is 12h and 18min.
On the first day of the month, sunrise is at 7:01 am and sunset at 7:39 pm. On the last day of September, in Surfside, sunrise is at 7:12 am and sunset at 7:07 pm EDT.

Sunshine

The average sunshine in September is 9h.

UV index

May through September, with an average maximum UV index of 7, are months with the highest UV index in Surfside. A UV Index estimate of 6 to 7 represents a high threat to health from unsafe exposure to UV radiation for average individuals.
Note: The UV index of 7 in September translates into these instructions:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. The Sun's UV radiation is at its strongest between the hours of 10 a.m. and 4 p.m. Minimize direct exposure to the sun during this period. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Take caution! The UV rays from the Sun gain strength from sand and water reflections.