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

Miami, Florida, starts September with an average high-temperature of a moderately hot 85.6°F (29.8°C), hinting at a minimal fluctuation from August. In Miami, the nightly September temperatures experience a slight descent from daily highs to an average low of 81°F (27.2°C).

Heat index

September's heat index is estimated at a fiery hot 95°F (35°C). Take greater precautions, heat exhaustion and heat cramps may be expected. Heatstroke could result from lengthy activity.
Realize that the values for the heat index are set for shaded places and light winds. Heat index values can rise by 15 Fahrenheit (8 Celsius) degrees when in direct sunlight.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', ties air temperature with relative humidity to produce the perceived temperature sensation. 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. Direct sun rays have a notable impact on perceived temperature, which can raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are largely significant for babies and toddlers. Youngsters frequently overlook the need for breaks and fluid intake. Thirst is an advanced sign of dehydration - thereby highlighting the importance of keeping hydrated, particularly during long physical activities.
The human body keeps its cool primarily through perspiration, as this process enables sweat to evaporate, taking away the excess heat. Elevated relative humidity diminishes evaporation, thereby reducing the body's ability to shed heat and creating a feeling of being too warm. Heat-related complications, like dehydration, can manifest if the body's heat gain exceeds its dissipation capacity.

Humidity

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

Rainfall

In Miami, in September, during 24.5 rainfall days, 1.93" (49mm) of precipitation is typically accumulated. In Miami, during the entire year, the rain falls for 182.7 days and collects up to 16.38" (416mm) of precipitation.

Ocean temperature

In Miami, the average seawater temperature in September is 85.5°F (29.7°C).
Note: For any water activity, the surface water temperatures in the range of 77°F (25°C) to 84.2°F (29°C) are deemed excellent and incredibly pleasant for longer durations.

Daylight

In September, the average length of the day 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. A UV Index of 6 to 7 symbolizes a high health hazard from unsafe exposure to UV radiation for average individuals.
Note: The maximum UV index of 7 during September translates into these guidelines:
Avoid excessive sunlight. Those with lighter skin may experience burning in less than 20 minutes. Avoid direct Sun exposure and seek shade between 10 a.m. and 4 p.m., when UV radiation is at its peak, but keep in mind that not all shade structures provide complete protection. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Note! The Sun's UV radiation gets intensified with the reflection from sand and water.