September weather forecast
Old Jefferson, LA

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Weather in September

September, the first month of the autumn in Old Jefferson, is still a tropical month, with an average temperature varying between 70.3°F (21.3°C) and 87.8°F (31°C).

Temperature

The transition from August to September sees an average high-temperature of a still tropical 87.8°F (31°C), indicating a minor variance from the prior month. Old Jefferson experiences a consistent average temperature of 70.3°F (21.3°C) throughout the nights in September.

Heat index

September's mean heat index is evaluated at a scorching 105.8°F (41°C). Incorporate extra safety measures to avoid heat exhaustion and heat cramps. Continuous activity could provoke heatstroke.
Note that heat index values are valued for light wind and location in the shade. Direct sunlight might lead to a heat index increase by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', blends air temperature and moisture content to represent the felt temperature to humans. The impact of temperature is individual, as people's perception of weather may change based on their body mass, height, and physical activity. Being under direct sunshine can magnify the heat experience, possibly pushing up the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly meaningful for babies and toddlers. Young individuals are typically more threatened than adults due to their reduced perspiration. Also, the larger skin surface proportionate to their small bodies and the increased heat from their activities magnify their risk.
To offset high temperatures, the human body releases sweat which, upon evaporation, cools it down. In situations of high air temperature combined with high humidity (significant heat index), the body's ability to perspire is reduced, heightening the sense of warmth. Should the body fail to balance its heat gain, the escalating temperature poses health challenges.

Humidity

The average relative humidity in September in Old Jefferson, Louisiana, is 79%.

Rainfall

In September, the rain falls for 18.6 days. Throughout September, 3.27" (83mm) of precipitation is accumulated. In Old Jefferson, during the entire year, the rain falls for 187.5 days and collects up to 40" (1016mm) of precipitation.

Snowfall

February through November are months without snowfall in Old Jefferson.

Daylight

In September, the average length of the day in Old Jefferson is 12h and 20min.
On the first day of the month, sunrise is at 6:41 am and sunset at 7:26 pm. On the last day of September, sunrise is at 6:57 am and sunset at 6:50 pm CDT.

Sunshine

In Old Jefferson, the average sunshine in September is 9.7h.

UV index

The average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health risk from unprotected exposure to Sun's UV rays for average individuals.
Note: The UV index of 6 in September translates into these instructions:
Take precautions against overexposure. Protection against sun damage is needed. The Sun's UV radiation is at its strongest between the hours of 10 a.m. and 4 p.m. Minimize direct exposure to the sun during this period. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
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Frequently asked questions

Is it hot in Old Jefferson during September?

In Old Jefferson, 87.8°F (31°C) is the average high-temperature and 70.3°F (21.3°C) is the average low-temperature during September. The average heat index (a.k.a. 'real feel', 'feels like'), which combines air temperature and relative humidity, in September is evaluated at 105.8°F (41°C).

What is the average humidity in September in Old Jefferson?

The average relative humidity in September in Old Jefferson is 79%.

How many days does it rain in September in Old Jefferson?

In Old Jefferson, Louisiana, in September, during 18.6 rainfall days, 3.27" (83mm) of precipitation is typically accumulated.

When it does not snow in Old Jefferson?

In Old Jefferson, Louisiana, snow does not fall in February through November.

What is the average length of the day in September in Old Jefferson?

In Old Jefferson, Louisiana, the average day length in September is 12h and 20min.

When is the sunrise / sunset in September in Old Jefferson?

On the first day of September in Old Jefferson, sunrise is at 6:41 am and sunset at 7:26 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:50 pm CDT.

How long on average sun shines in September in Old Jefferson?

In September, the average sunshine duration in Old Jefferson is 9.7h.

What is the UV index reading in September in Old Jefferson?

In Old Jefferson, Louisiana, the average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Old Jefferson, LA

Average temperature in September - Old Jefferson, LA
  • Average high temperature in September: 87.8°F

The warmest month (with the highest average high temperature) is July (91.6°F).
The month with the lowest average high temperature is January (59°F).

  • Average low temperature in September: 70.3°F

The month with the highest average low temperature is August (74.7°F).
The coldest month (with the lowest average low temperature) is January (43.2°F).

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Average pressure in September
Old Jefferson, LA

Average pressure in September - Old Jefferson, LA
  • Average pressure in September: 29.97"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The months with the lowest atmospheric pressure are June and August (29.96"Hg).

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Average wind speed in September
Old Jefferson, LA

Average wind speed in September - Old Jefferson, LA
  • Average wind speed in September: 4.7mph

The windiest month (with the highest average wind speed) is February (6.8mph).
The calmest months (with the lowest average wind speed) are July and August (4.5mph).

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Average humidity in September
Old Jefferson, LA

Average humidity in September - Old Jefferson, LA
  • Average humidity in September: 79%

The months with the highest relative humidity are February and December (81%).
The month with the lowest relative humidity is October (73%).

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Average rainfall in September
Old Jefferson, LA

Average rainfall in September - Old Jefferson, LA
  • Average rainfall in September: 3.27"

The wettest month (with the highest rainfall) is July (5.47").
The driest month (with the least rainfall) is November (1.93").

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Average rainfall days in September
Old Jefferson, LA

Average rainfall days in September - Old Jefferson, LA
  • Average rainfall days in September: 18.6 days

The month with the highest number of rainy days is August (23.8 days).
The month with the least rainy days is November (8.9 days).

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Average snowfall in September
Old Jefferson, LA

Average snowfall in September - Old Jefferson, LA
  • Average snowfall in September: 0"

The month with the highest snowfall is January (0.2").
The months with the least snowfall are February, March, April, May, June, July, August, September, October and November (0").

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Average snowfall days in September
Old Jefferson, LA

Average snowfall days in September - Old Jefferson, LA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (0.3 days).
The months with the least snowfall days are February, March, April, May, June, July, August, September, October and November (0 days).

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Average daylight in September /
Average sunshine in September
Old Jefferson, LA

Average daylight in September / Average sunshine in September - Old Jefferson, LA
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 6min).
The month with the shortest days is December (Average daylight: 10h and 12min).

  • Average sunshine in September: 9h and 4min

The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is December (Average sunshine: 5h and 0min).

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Average sunshine days in September
Old Jefferson, LA

Average sunshine days in September - Old Jefferson, LA
  • Average sunshine days in September: 9.5 days

The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is July (5.9 days).

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Average UV index in September
Old Jefferson, LA

Average UV index in September - Old Jefferson, LA
  • Average UV index in September: 6

The months with the highest UV index are May, June, July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).

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Average cloud cover in September
Old Jefferson, LA

Average cloud cover in September - Old Jefferson, LA
  • Average cloud cover in September: 31

The month with the most cloud cover is December (Cloud cover 48).
The month with the least cloud cover is October (Cloud cover 27).

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Average visibility in September
Old Jefferson, LA

Average visibility in September - Old Jefferson, LA
  • Average visibility in September: 5mi

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

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Old Jefferson, Louisiana, USA

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