September weather forecast and climate
Keystone, FL

Weather in September

The first month of the autumn, September, is still a tropical month in Keystone, Florida, with average temperature varying between 86.7°F (30.4°C) and 77.5°F (25.3°C).

Temperature

In Keystone, the average high-temperature is essentially the same as in August - a still tropical 86.7°F (30.4°C). The average low-temperature,, is 77.5°F (25.3°C).

Heat index

The average heat index is evaluated at a sweltering 99.3°F (37.4°C). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature', 'feels like', 'apparent temperature', or 'real feel', is what the temperature feels like to the human body when the air temperature is combined with the relative humidity. Additional factors like activity, metabolic differences, wind, and pregnancy affect individual temperature impact. Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.
The human body normally cools itself by perspiration. Excessive warmth is eliminated from the body by evaporation of sweat. 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

The average relative humidity in September is 75%.

Rainfall

In September, in Keystone, Florida, the rain falls for 15.7 days. Throughout September, 0.71" (18mm) of precipitation is accumulated. Throughout the year, in Keystone, Florida, there are 120.5 rainfall days, and 9.45" (240mm) of precipitation is accumulated.

Daylight

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

Sunshine

The average sunshine in September is 9.2h.

UV index

May through September, 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 vulnerability from unprotected exposure to the Sun's UV rays for the average person.
Note: The daily maximum UV index of 7 interpret into the following advice:
Take precautions and utilize sun safety practices. Protection against the skin and eye damage is required. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.
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FAQ

What is the temperature in September in Keystone?

In September, in Keystone, Florida, the average high-temperature is 86.7°F (30.4°C), and the average low-temperature is 77.5°F (25.3°C). In September, the average heat index (a.k.a. 'feels like', 'real feel'), which combines air temperature and relative humidity, is evaluated at 99.3°F (37.4°C).

What is the average humidity in September in Keystone?

In Keystone, Florida, the average relative humidity in September is 75%.

How many days does it rain in September in Keystone?

In Keystone, during September, the rain falls for 15.7 days and regularly aggregates up to 0.71" (18mm) of precipitation.

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

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

How many hours of sunshine does Keystone have in September?

In Keystone, the average sunshine in September is 9.2h.

What is the month with the highest UV index in Keystone?

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

What is the UV index reading in September in Keystone?

In September, the average daily maximum UV index in Keystone, Florida, is 7. A UV Index reading of 6 to 7 represents a high health risk from unprotected exposure to the UV radiation.

Average temperature in September
Keystone, FL

Average temperature in September - Keystone, FL
  • Average high temperature in September: 86.7°F

The warmest month (with the highest average high temperature) is August (88.3°F).
The month with the lowest average high temperature is January (66°F).

  • Average low temperature in September: 77.5°F

The month with the highest average low temperature is August (80.2°F).
The coldest month (with the lowest average low temperature) is January (54.5°F).

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Average pressure in September
Keystone, FL

Average pressure in September - Keystone, FL
  • Average pressure in September: 29.96"

The month with the highest atmospheric pressure is January (30.14").
The month with the lowest atmospheric pressure is September (29.96").

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Average wind speed in September
Keystone, FL

Average wind speed in September - Keystone, FL
  • Average wind speed in September: 7.3mph

The windiest months (with the highest average wind speed) are January, March and April (8.9mph).
The calmest month (with the lowest average wind speed) is July (6.7mph).

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Average humidity in September
Keystone, FL

Average humidity in September - Keystone, FL
  • Average humidity in September: 75%

The month with the highest relative humidity is December (77%).
The month with the lowest relative humidity is May (72%).

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Average rainfall in September
Keystone, FL

Average rainfall in September - Keystone, FL
  • Average rainfall in September: 0.71"

The wettest month (with the highest rainfall) is July (1.77").
The driest month (with the least rainfall) is March (0.2").

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Average rainfall days in September
Keystone, FL

Average rainfall days in September - Keystone, FL
  • Average rainfall days in September: 15.7 days

The month with the highest number of rainy days is August (17.9 days).
The month with the least rainy days is November (5.5 days).

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Average daylight in September /
Average sunshine in September
Keystone, FL

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

The month with the longest days is June (Average daylight: 13.9h).
The month with the shortest days is December (Average daylight: 10.4h).

  • Average sunshine in September: 9.2h

The month with the most sunshine is May (Average sunshine: 11.3h).
The month with the least sunshine is December (Average sunshine: 6.5h).

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Average sunshine days in September
Keystone, FL

Average sunshine days in September - Keystone, FL
  • Average sunshine days in September: 10.6 days

The month with the most sunshine days is January (23.4 days).
The month with the least sunshine days is July (6.7 days).

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Average UV index in September
Keystone, FL

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

Months with the highest UV index are May, June, July, August and September (UV index 7).
The month with the lowest UV index is January (UV index 4).

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Average cloud cover in September
Keystone, FL

Average cloud cover in September - Keystone, FL
  • Average cloud cover in September: 26

Months with the most cloud cover are January and December (Cloud cover 30).
The month with the least cloud cover is May (Cloud cover 20).

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Average visibility in September
Keystone, FL

Average visibility in September - Keystone, FL
  • Average visibility in September: 6mi

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

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