September weather forecast and climate
Key, AL

Weather in September

The first month of the autumn, September, is still a warm month in Key, Alabama, with average temperature ranging between max 82.9°F (28.3°C) and min 62.6°F (17°C).

Temperature

In Key, the average high-temperature is almost the same as in August - a warm 82.9°F (28.3°C). In Key, the average low-temperature is 62.6°F (17°C).

Heat index

The average heat index in September is calculated to a hot 89.6°F (32°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', 'apparent temperature', 'feels like', or 'real feel', is a measure of how hot it feels when the actual air humidity is factored in. Additional factors like differences in body mass, height, and shape, metabolic differences, wind, and activity influence one's weather impression. Be aware that direct exposure to sunlight increases heat impact, and may raise the heat index additionally, by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. 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.

Humidity

In September, the average relative humidity is 75%.

Rainfall

In Key, during September, the rain falls for 14.2 days and regularly aggregates up to 2.72" (69mm) of precipitation. In Key, during the entire year, the rain falls for 181.2 days and collects up to 41.06" (1043mm) of precipitation.

Snowfall

April through October are months without snowfall in Key.

Daylight

In Key, the average length of the day is 12.4h.

Sunshine

In September, the average sunshine is 8.5h.

UV index

In Key, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from unsafe exposure to the UV radiation for ordinary individuals.
Note: The daily maximum UV index of 5 in September interpret into the following advice:
Take precautions - Protection against sun damage is advised. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the temperature in September in Key?

In September, the average high-temperature is 82.9°F (28.3°C), and the average low-temperature is 62.6°F (17°C). The average heat index (a.k.a. 'felt air temperature', 'real feel'), that combines air temperature and relative humidity, in September is calculated to 89.6°F (32°C).

What is the average humidity in September in Key?

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

How much does it rain in Key in September?

In Key, Alabama, during September, the rain falls for 14.2 days and regularly aggregates up to 2.72" (69mm) of precipitation.

When it does not snow in Key?

April through October are months without snowfall in Key.

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

In September, the average length of the day in Key is 12.4h.

How long on average sun shines in September in Key?

In September, the average sunshine is 8.5h.

What is the UV index intensity in September in Key?

In Key, Alabama, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate vulnerability from the exposure to the Sun's UV rays.

Average temperature in September
Key, AL

Average temperature in September - Key, AL
  • Average high temperature in September: 82.9°F

The warmest month (with the highest average high temperature) is July (88.7°F).
The month with the lowest average high temperature is January (48.9°F).

  • Average low temperature in September: 62.6°F

The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (33.4°F).

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Average pressure in September
Key, AL

Average pressure in September - Key, AL
  • Average pressure in September: 30.02"

The month with the highest atmospheric pressure is January (30.17").
The month with the lowest atmospheric pressure is June (29.98").

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Average wind speed in September
Key, AL

Average wind speed in September - Key, AL
  • Average wind speed in September: 4.5mph

The windiest month (with the highest average wind speed) is February (7.3mph).
The calmest month (with the lowest average wind speed) is August (4.1mph).

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Average humidity in September
Key, AL

Average humidity in September - Key, AL
  • Average humidity in September: 75%

The month with the highest relative humidity is December (80%).
The month with the lowest relative humidity is October (74%).

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Average rainfall in September
Key, AL

Average rainfall in September - Key, AL
  • Average rainfall in September: 2.72"

The wettest months (with the highest rainfall) are February and December (4.06").
The driest month (with the least rainfall) is October (2.56").

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Average rainfall days in September
Key, AL

Average rainfall days in September - Key, AL
  • Average rainfall days in September: 14.2 days

The month with the highest number of rainy days is July (21.1 days).
The month with the least rainy days is November (9.8 days).

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Average snowfall in September
Key, AL

Average snowfall in September - Key, AL
  • Average snowfall in September: 0"

The month with the highest snowfall is January (0.79").
Months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in September
Key, AL

Average snowfall days in September - Key, AL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (1.4 days).
Months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average daylight in September /
Average sunshine in September
Key, AL

Average daylight in September / Average sunshine in September - Key, AL
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 14.4h).
The month with the shortest days is December (Average daylight: 9.9h).

  • Average sunshine in September: 8.5h

Months with the most sunshine are June and July (Average sunshine: 10.6h).
The month with the least sunshine is February (Average sunshine: 4.8h).

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Average sunshine days in September
Key, AL

Average sunshine days in September - Key, AL
  • Average sunshine days in September: 13.4 days

The month with the most sunshine days is October (19.1 days).
The month with the least sunshine days is July (8 days).

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Average UV index in September
Key, AL

Average UV index in September - Key, AL
  • Average UV index in September: 5

Months with the highest UV index are May, June, July and August (UV index 6).
Months with the lowest UV index are January and December (UV index 2).

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Average cloud cover in September
Key, AL

Average cloud cover in September - Key, AL
  • Average cloud cover in September: 31

The month with the most cloud cover is February (Cloud cover 48).
The month with the least cloud cover is June (Cloud cover 30).

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Average visibility in September
Key, AL

Average visibility in September - Key, AL
  • Average visibility in September: 6mi

Months with the highest visibility are February, March, April, May, June, July, August, September, October and November (6mi).
Months with the lowest visibility are January and December (5mi).

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