September weather forecast
Miami, FL

In September, Miami, Florida experiences a gradual decline in temperature marking the end of the sweltering summer season. The saturated air, attaining the year's highest humidity of 73%, is a significant feature this month. Compared to the preceding month, September is cooler yet maintains a similar pattern of afternoon thunderstorms. The city starts to witness a decrease in temperature and humidity, providing a respite from the peak summer conditions. Moving into October, residents can expect the onset of drier and more pleasant weather conditions.

Temperature

With the transition into September, Miami notes an average high-temperature of a moderately hot 85.6°F (29.8°C), closely resembling August. Miami's nocturnal average in September closely mirrors its daytime temperatures, settling at 81°F (27.2°C).

Heat index

September's average heat index is computed to be a very hot 95°F (35°C). Take more safety measures, heat exhaustion and heat cramps are potential outcomes. Persistent activity might lead to heatstroke.
Remember that heat index calculations are made for conditions in the shade with light wind. A direct sunlight exposure may boost the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'apparent temperature', is a composite of temperature and humidity figures to convey how warm it feels. The individual's temperature perception can be influenced by numerous factors such as metabolic variations, physical activity, and clothing. Exposure to direct sun rays can influence the heat you feel, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Children frequently do not comprehend the need for rest and hydration. Thirst is an advanced stage of dehydration - staying hydrated, especially during extended physical exercises, is essential.
Sweat evaporation plays a crucial role in cooling the human body, a process enabled by perspiration. Under conditions of increased relative humidity, the evaporation rate lessens, causing the body to retain more heat than under less humid conditions. When the body's heat gain surpasses its removal capacity, body temperature starts to climb, leading to potential heat-related ailments.

Humidity

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

Rainfall

In Miami, Florida, in September, it is raining for 24.5 days, with typically 1.93" (49mm) of accumulated precipitation. Throughout the year, there are 182.7 rainfall days, and 16.38" (416mm) of precipitation is accumulated.

Ocean temperature

In September, the average ocean temperature in Miami is 85.5°F (29.7°C).
Note: For activities in the water such as swimming or diving, temperatures from 77°F (25°C) to 84.2°F (29°C) are considered optimal for prolonged enjoyment without discomfort.

Daylight

The average length of the day in September is 12h and 17min.
On the first day of September, sunrise is at 7:01 am and sunset at 7:39 pm. On the last day of the month, sunrise is at 7:12 am and sunset at 7:08 pm EDT.

Sunshine

The average sunshine in September is 9.1h.

UV index

May through October, with an average maximum UV index of 7, are months with the highest UV index in Miami, Florida. A UV Index value of 6 to 7 symbolizes a high threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: A maximum high UV index of 7 in September translates into the following recommendations:
Act on precautions and pay attention to sun safety recommendations. Avoidance of sunburn is obligatory. Seek shade and limit direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Keep in mind that shade structures like parasols or canopies do not offer complete sun protection. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses. Attention! The combination of sand and water reflections enhances UV ray intensity.