Miami
Florida, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Miami, FL

The first month of the autumn, September, is still a warm month in Miami, Florida, with average temperature ranging between min 81°F (27.2°C) and max 85.6°F (29.8°C).

Temperature

In September, the average high-temperature is relatively the same as in August - a moderately hot 85.6°F (29.8°C). In Miami, in September, the average low-temperature is 81°F (27.2°C).

Heat index

In September, the average heat index is evaluated at a sweltering 95.5°F (35.3°C). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Note that heat index values are valued for light wind and location in the shade. With the exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature', 'real feel', 'apparent temperature', or 'feels like', is a measure of how hot it feels when the actual air humidity is factored in. Additional factors like activity, metabolic differences, wind, and clothing affect individual temperature impact. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
To prevent overheating and help regulate its internal temperature, the human body sweat and rely on the evaporation to cool down. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

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

Rainfall

In Miami, during September, the rain falls for 24.5 days and regularly aggregates up to 1.93" (49mm) of precipitation. 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, Florida, the average water temperature is 85.5°F (29.7°C).
Note: For swimming, diving, and other water activities, temperatures between 77°F (25°C) and 84.2°F (29°C) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

Daylight

The average length of the day in September is 12.3h.

Sunshine

In September, the average sunshine 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. A UV Index estimate of 6 to 7 represents a high threat to health from the exposure to the Sun's UV radiation for average individuals.
Note: The average daily UV index of 7 in September transform into the following instructions:
Take precautions against overexposure. Fair-skinned people may get burned in less than 20 minutes. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.

What is the temperature in September in Miami?

In Miami, Florida, in September, the average high-temperature is 85.6°F (29.8°C), and the average low-temperature is 81°F (27.2°C). The average heat index (a.k.a. 'felt air temperature', 'feels like'), that represents influence of the relative humidity to air temperaure, in September is calculated to 95.5°F (35.3°C).

What is the average humidity in September in Miami?

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

How much does it rain in Miami in September?

In Miami, in September, during 24.5 rainfall days, 1.93" (49mm) of precipitation is typically accumulated.

What is the water temperature in September in Miami?

In Miami, the average seawater temperature in September is 85.5°F (29.7°C). For swimming, diving, and other water activities, temperatures between 77°F (25°C) and 84.2°F (29°C) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

What is the average length of the day in September in Miami?

In Miami, Florida, the average length of the day in September is 12.3h.

How many hours of sunshine does Miami have in September?

In Miami, Florida, the average sunshine in September is 9.1h.

What are the months with the highest UV index in Miami?

Months with the highest UV index are May through October, with an average maximum UV index of 7.

What is the UV index reading in September in Miami?

The average daily maximum UV index in September is 7. A UV Index value of 6 to 7 symbolizes a high health risk from the exposure to the Sun's UV rays.
Average temperature in September - Miami, FL
  • Average high temperature in September: 29.8°C

The warmest month (with the highest average high temperature) is August (30.6°C).
The month with the lowest average high temperature is January (22.8°C).

  • Average low temperature in September: 27.2°C

The month with the highest average low temperature is August (28.1°C).
The coldest month (with the lowest average low temperature) is January (18.4°C).

Average humidity in September - Miami, FL
  • Average humidity in September: 73%

The month with the highest relative humidity is December (75%).
The month with the lowest relative humidity is March (70%).

Average rainfall in September - Miami, FL
  • Average rainfall in September: 49mm

The wettest month (with the highest rainfall) is August (71mm).
The driest month (with the least rainfall) is January (11mm).

Average rainfall days in September - Miami, FL
  • Average rainfall days in September: 24.5 days

The month with the highest number of rainy days is September (24.5 days).
The month with the least rainy days is February (8.7 days).

Average sea temperature in September - Miami, FL
  • Average sea temperature in September: 29.7°C

The best month for swimming (with the highest average sea temperature) is August (30.3°C).
The coldest month (with the lowest average sea temperature) is February (23.3°C).

Average daylight in September / Average sunshine in September - Miami, FL
  • Average daylight in September: 12.3h

The month with the longest days is June (Average daylight: 13.7h).
The month with the shortest days is December (Average daylight: 10.5h).

  • Average sunshine in September: 9.1h

The month with the most sunshine is July (Average sunshine: 11.1h).
The month with the least sunshine is December (Average sunshine: 6.4h).

Average UV index in September - Miami, FL
  • Average UV index in September: 7

Months with the highest UV index are May, June, July, August, September and October (UV index 7).
Months with the lowest UV index are January and December (UV index 5).