September weather forecast
Saint Lucie, FL

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Weather in September

September, the first month of the autumn in Saint Lucie, is still a warm month, with an average temperature ranging between max 85.8°F (29.9°C) and min 77.2°F (25.1°C).

Temperature

September's beginning signals an average high-temperature of a moderately hot 85.8°F (29.9°C), barely different from August's 87.6°F (30.9°C). Night temperatures during September stabilize at an average of 77.2°F (25.1°C), closely mirroring the daytime temperatures.

Heat index

In September, the average heat index is calculated to be a torrid 98.6°F (37°C). Ensure extra safety steps, heat exhaustion and heat cramps are likely. Long activity might lead to heatstroke.
Research indicates the heat index considers values in shaded locales and with light winds. With 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' or 'real feel', is a calculation that merges air temperature and relative humidity to depict the sensation of warmth. One's weather perception can be influenced by a range of factors including metabolic differences, being pregnant, and their level of physical activity. Given the impact of direct sunlight, it's noteworthy that the felt temperature can rise by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Children often lack awareness of the importance of taking breaks and rehydrating. The feeling of thirst is a late indication of dehydration, so maintaining hydration, especially during long periods of physical activity, is critical.
The process of perspiration is vital for the human body to get rid of excess warmth by allowing sweat to evaporate. An increase in relative humidity hinders the body's normal cooling function by reducing evaporation, thereby decreasing the rate of body cooling and enhancing the sense of warmth. 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

The average relative humidity in September in Saint Lucie, Florida, is 78%.

Rainfall

In September, the rain falls for 25.4 days. Throughout September, 5.55" (141mm) of precipitation is accumulated. Throughout the year, there are 221.2 rainfall days, and 46.26" (1175mm) of precipitation is accumulated.

Daylight

In September, the average length of the day is 12h and 19min.
On the first day of the month, sunrise is at 7:00 am and sunset at 7:41 pm. On the last day of September, sunrise is at 7:13 am and sunset at 7:08 pm EDT.

Sunshine

In September, the average sunshine is 8.8h.

UV index

The months with the highest UV index are May through September, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: In September, a regular UV index of 7 translates into these guidelines:
Ward off overexposure. Defence against solar harm is crucial. The Sun's UV radiation is most intense from 10 a.m. to 4 p.m. Try to avoid direct sun exposure during these hours. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.
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Frequently asked questions

How hot is it in Saint Lucie in September?

The average high-temperature, in September, in Saint Lucie, is 85.8°F (29.9°C), while the average low-temperature is 77.2°F (25.1°C). In September, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which factors the actual air temperature with the relative humidity, is calculated to be 98.6°F (37°C).

What is the average humidity in September in Saint Lucie?

In September, the average relative humidity is 78%.

How many days does it rain in September in Saint Lucie?

In Saint Lucie, Florida, in September, during 25.4 rainfall days, 5.55" (141mm) of precipitation is typically accumulated.

What is the average length of the day in September in Saint Lucie?

In September, the average day length in Saint Lucie is 12h and 19min.

When are sunrise and sunset in September in Saint Lucie?

On the first day of September, sunrise is at 7:00 am and sunset at 7:41 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 7:08 pm EDT.

How long on average sun shines in September in Saint Lucie?

In September, the average sunshine duration is 8.8h.

When is the highest UV index in Saint Lucie?

The months with the highest UV index are May through September, with an average maximum UV index of 7.

What is the UV index reading in September in Saint Lucie?

In September, the average daily maximum UV index in Saint Lucie is 7. A UV Index reading of 6 to 7 represents a high hazard to health from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Saint Lucie, FL

Average temperature in September - Saint Lucie, FL
  • Average high temperature in September: 85.8°F

The warmest month (with the highest average high temperature) is August (87.6°F).
The month with the lowest average high temperature is January (70.5°F).

  • Average low temperature in September: 77.2°F

The month with the highest average low temperature is August (78.4°F).
The coldest month (with the lowest average low temperature) is January (59.2°F).

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Average pressure in September
Saint Lucie, FL

Average pressure in September - Saint Lucie, FL
  • Average pressure in September: 29.96"Hg

The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is September (29.96"Hg).

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Average wind speed in September
Saint Lucie, FL

Average wind speed in September - Saint Lucie, FL
  • Average wind speed in September: 7.5mph

The windiest months (with the highest average wind speed) are January and March (9.4mph).
The calmest month (with the lowest average wind speed) is July (6.6mph).

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Average humidity in September
Saint Lucie, FL

Average humidity in September - Saint Lucie, FL
  • Average humidity in September: 78%

The month with the highest relative humidity is August (79%).
The month with the lowest relative humidity is March (72%).

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Average rainfall in September
Saint Lucie, FL

Average rainfall in September - Saint Lucie, FL
  • Average rainfall in September: 5.55"

The wettest month (with the highest rainfall) is August (8.23").
The driest month (with the least rainfall) is February (1.26").

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Average rainfall days in September
Saint Lucie, FL

Average rainfall days in September - Saint Lucie, FL
  • Average rainfall days in September: 25.4 days

The month with the highest number of rainy days is August (28.1 days).
The month with the least rainy days is January (11.3 days).

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Average daylight in September /
Average sunshine in September
Saint Lucie, FL

Average daylight in September / Average sunshine in September - Saint Lucie, FL
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 13h and 54min).
The month with the shortest days is December (Average daylight: 10h and 24min).

  • Average sunshine in September: 8h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 5h and 54min).

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Average sunshine days in September
Saint Lucie, FL

Average sunshine days in September - Saint Lucie, FL
  • Average sunshine days in September: 2.5 days

The month with the most sunshine days is January (17 days).
The month with the least sunshine days is August (0.8 days).

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Average UV index in September
Saint Lucie, FL

Average UV index in September - Saint Lucie, FL
  • Average UV index in September: 7

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

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Average cloud cover in September
Saint Lucie, FL

Average cloud cover in September - Saint Lucie, FL
  • Average cloud cover in September: 32

The months with the most cloud cover are November and December (Cloud cover 37).
The month with the least cloud cover is May (Cloud cover 28).

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Average visibility in September
Saint Lucie, FL

Average visibility in September - Saint Lucie, FL
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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Saint Lucie, Florida, USA

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