September weather forecast
Old Jefferson, LA

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Weather in September

The first month of the autumn, September, is also a hot month in Old Jefferson, Louisiana, with an average temperature ranging between min 70.3°F (21.3°C) and max 87.8°F (31°C).

Temperature

An average high-temperature of a still hot 87.8°F (31°C) marks September, exhibiting a close resemblance to the conditions in August. Old Jefferson, during September nights, observes an average temperature of 70.3°F (21.3°C).

Heat index

During September, the heat index is evaluated at a blistering 105.8°F (41°C). Heightened precautions are necessary, heat cramps and heat exhaustion are potential risks. Continuous activity could lead to heatstroke.
Realize that the values for the heat index are set for shaded places and light winds. Heat index values have the potential to be boosted by 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'apparent temperature' or 'feels like', provides an understanding of perceived warmth by combining temperature and relative humidity. The influence of weather can be personal, changing with an individual's body mass, height, and level of physical exertion. It is important to note that direct sunlight can intensify the weather impact, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Young individuals are generally in more danger than adults due to their lower capacity to sweat. Moreover, their large skin surface in relation to their small bodies and the increased heat generation from their activities makes them more vulnerable.
By perspiring, the human body can shed its excessive warmth since evaporated sweat cools it off. An upsurge in relative humidity affects normal body cooling mechanisms by slowing evaporation, hence reducing the rate at which the body cools and intensifying the perception of heat. When the body is unable to balance heat gain, its temperature elevates, which may induce thermal illnesses.

Humidity

In Old Jefferson, the average relative humidity in September is 79%.

Rainfall

In Old Jefferson, during September, the rain falls for 18.6 days and regularly aggregates up to 3.27" (83mm) of precipitation. 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.

Daylight

The average length of the day in September is 12h and 20min.
On the first day of September, 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.

Sunshine

In September, the average sunshine is 9.7h.

UV index

In Old Jefferson, the average daily maximum UV index in September is 6. A UV Index value of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV rays for ordinary individuals.
Note: A maximum daily UV index of 6 during September morphs into the following directions:
Stay clear of intense sun exposure. Solar protection is of utmost significance. Seek shade and limit direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Keep in mind that shade structures like parasols or canopies do not offer complete sun protection. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear.
Updated: Jun 25, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is 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. In September, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which represents the influence of relative humidity on air temperature, is evaluated at 105.8°F (41°C).

What is the average humidity in September?

In September, the average relative humidity is 79%.

How much does it rain in September?

In Old Jefferson, during September, the rain falls for 18.6 days and regularly aggregates up to 3.27" (83mm) of precipitation.

When it does not snow?

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

How many hours of daylight does Old Jefferson have in September?

In September, the average day length is 12h and 20min.

When are sunrise and sunset in September in Old Jefferson?

On the first day of September, 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 many hours of sunshine does Old Jefferson have in September?

The average sunshine duration in September in Old Jefferson is 9.7h.

How high is the UV index in September?

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

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).

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).

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%).

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").

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).

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").

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).

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).

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).

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).

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).

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).

Old Jefferson, Louisiana, USA

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