September weather forecast
Gretna, LA

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Weather in September

September beckons the start of more clement weather in Gretna with a decrease in temperatures. Decreased rainfall of 0.47" (12mm) signals drier days. Average sunlight hours start to decline, thus signaling the advent of autumn. The slight increase in wind speed results in cooler nights, preparing residents for the upcoming change in month and weather. However, with a consistent UV index of 7, outdoor activities still remain a joy.

Temperature

As September takes its course, Gretna's average high-temperature registers at a still tropical 86.5°F (30.3°C), closely aligning with the preceding month. Gretna's average low-temperature is measured at a moderately hot 76.3°F (24.6°C) during September.

Heat index

During September, the heat index is computed to be a torrid 98.6°F (37°C). Exercise more precautions, heat cramps and heat exhaustion are potential risks. Continuous activity could precipitate heatstroke.
It is worth noting that heat index values are gauged for conditions in the shade and light breezes. With exposure to direct sunshine, the heat index could climb by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', arises from combining readings of air temperature and relative moisture content. An individual's temperature experience can be influenced by extra factors, including metabolic differences, activity levels, and clothing. When directly under the sun, the weather's impact can intensify, possibly boosting the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are essentially critical for children. Kids often lack the knowledge about the necessity to take breaks and consume liquids. Thirst, as a late symptom of dehydration, necessitates the maintenance of hydration, particularly during enduring physical activities.
Evaporating sweat, an outcome of perspiration, is key in assisting the human body to moderate its temperature. Under conditions of increased relative humidity, the evaporation rate lessens, causing the body to retain more heat than under less humid conditions. Rising body temperatures due to excess heat retention could signify impending heat disorders.

Humidity

The average relative humidity in September in Gretna is 73%.

Rainfall

In September, the rain falls for 11.7 days. Throughout September, 0.47" (12mm) of precipitation is accumulated. In Gretna, during the entire year, the rain falls for 112.1 days and collects up to 9.37" (238mm) of precipitation.

Snowfall

In Gretna, Louisiana, snow does not fall in February through December.

Daylight

The average length of the day in September is 12h and 20min.
On the first day of the month, sunrise is at 6:37 am and sunset at 7:22 pm. On the last day of September, sunrise is at 6:53 am and sunset at 6:46 pm CDT.

Sunshine

In September, the average sunshine is 10.1h.

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 threat to health from unsafe exposure to UV radiation for the ordinary person.
Note: The maximum daily UV index of 7 in September interprets into the following recommendations:
Undertake protective measures and comply with sun safety rules. Shielding against skin and eye damage is essential. From 10 a.m. to 4 p.m., when UV radiation is at its strongest, limit direct exposure to the Sun and note that shade structures may not provide full sun protection. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.

Frequently asked questions

How hot does it get in September?

September temperatures vary between a high-temperature of 86.5°F (30.3°C) and a low-temperature of 76.3°F (24.6°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which takes the relative humidity and factors it into the air temperature reading, in September is computed to be 98.6°F (37°C).

What is the average humidity in September?

In September, the average relative humidity is 73%.

How many days does it rain in September?

In Gretna, Louisiana, in September, it is raining for 11.7 days, with typically 0.47" (12mm) of accumulated precipitation.

When it does not snow?

February through December are months without snowfall.

What is the average length of the day in September?

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

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:37 am and sunset at 7:22 pm. On the last day of the month, sunrise is at 6:53 am and sunset at 6:46 pm CDT.

How many hours of sunshine does Gretna have in September?

In September, the average sunshine duration is 10.1h.

What is the month with the highest UV index?

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

What is the UV index intensity in September?

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

Average temperature in September
Gretna, LA

Average temperature in September - Gretna, LA
  • Average high temperature in September: 86.5°F

The warmest months (with the highest average high temperature) are July and August (89.4°F).
The month with the lowest average high temperature is January (60.4°F).

  • Average low temperature in September: 76.3°F

The month with the highest average low temperature is August (79.5°F).
The coldest month (with the lowest average low temperature) is January (48.6°F).

Average pressure in September
Gretna, LA

Average pressure in September - Gretna, 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, August and September (29.97"Hg).

Average wind speed in September
Gretna, LA

Average wind speed in September - Gretna, LA
  • Average wind speed in September: 7.1mph

The windiest months (with the highest average wind speed) are February and April (9.8mph).
The calmest month (with the lowest average wind speed) is July (6.6mph).

Average humidity in September
Gretna, LA

Average humidity in September - Gretna, LA
  • Average humidity in September: 73%

The months with the highest relative humidity are February and December (77%).
The month with the lowest relative humidity is October (71%).

Average rainfall in September
Gretna, LA

Average rainfall in September - Gretna, LA
  • Average rainfall in September: 0.47"

The wettest month (with the highest rainfall) is July (1.57").
The driest months (with the least rainfall) are March and April (0.43").

Average rainfall days in September
Gretna, LA

Average rainfall days in September - Gretna, LA
  • Average rainfall days in September: 11.7 days

The month with the highest number of rainy days is August (17.2 days).
The month with the least rainy days is November (4.7 days).

Average snowfall days in September
Gretna, LA

Average snowfall days in September - Gretna, LA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (0.1 days).
The months with the least snowfall days are February, March, April, May, June, July, August, September, October, November and December (0 days).

Average daylight in September /
Average sunshine in September
Gretna, LA

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

The month with the longest days is June (Average daylight: 14h and 0min).
The month with the shortest days is December (Average daylight: 10h and 18min).

  • Average sunshine in September: 10h and 1min

The month with the most sunshine is June (Average sunshine: 11h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 6min).

Average sunshine days in September
Gretna, LA

Average sunshine days in September - Gretna, LA
  • Average sunshine days in September: 12.5 days

The month with the most sunshine days is November (23.5 days).
The month with the least sunshine days is August (8.9 days).

Average UV index in September
Gretna, LA

Average UV index in September - Gretna, LA
  • Average UV index in September: 7

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

Average cloud cover in September
Gretna, LA

Average cloud cover in September - Gretna, LA
  • Average cloud cover in September: 25

The month with the most cloud cover is December (Cloud cover 44).
The month with the least cloud cover is October (Cloud cover 24).

Average visibility in September
Gretna, LA

Average visibility in September - Gretna, LA
  • 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).

Gretna, Louisiana, USA

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