September weather forecast
Louisville, IL

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Weather in September

September, the first month of the autumn in Louisville, is still a warm month, with temperature in the range of an average high of 78.6°F (25.9°C) and an average low of 59.9°F (15.5°C).

Temperature

Welcoming September, Louisville notes an average high-temperature of a still warm 78.6°F (25.9°C), nearly consistent with August's 82.9°F (28.3°C). Louisville sees an average low-temperature of 59.9°F (15.5°C) during September.

Humidity

In September, the average relative humidity in Louisville is 74%.

Rainfall

February and September are months with the least rain in Louisville when the rain falls for 13.3 days and typically aggregates up to 2.09" (53mm) of rain.

Snowfall

May through September are months without snowfall.

Daylight

In Louisville, the average length of the day in September is 12h and 26min.
On the first day of the month, sunrise is at 6:23 am and sunset at 7:23 pm. On the last day of September, sunrise is at 6:49 am and sunset at 6:37 pm CDT.

Sunshine

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

UV index

The average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the ordinary person.
Note: The maximum UV index of 5 during September leads to these instructions:
Exercise care. People with light skin might get burns in fewer than 30 minutes. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September in Louisville?

In Louisville, in September, the average high-temperature is 78.6°F (25.9°C), and the average low-temperature is 59.9°F (15.5°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which combines relative humidity and air temperature, in August is appraised at 91.4°F (33°C).

What is the average humidity in September in Louisville?

The average relative humidity in September in Louisville is 74%.

What is the driest month in Louisville?

The months with the least rainfall are February and September Rain falls for 13.3 days and accumulates 2.09" (53mm) of rain.

How many days does it rain in September in Louisville?

In September, the rain falls for 13.3 days. Throughout September, 2.09" (53mm) of precipitation is accumulated.

When it does not snow in Louisville?

In Louisville, snow does not fall in May through September.

Does it snow in Louisville in September?

In Louisville, in September, it doesn't snow. In October, it regularly snows.

How many hours of daylight does Louisville have in September?

In Louisville, Illinois, the average day length in September is 12h and 26min.

When are sunrise and sunset in September in Louisville?

In September, on the first day of the month, sunrise is at 6:23 am and sunset at 7:23 pm. On the last day of the month, in Louisville, sunrise is at 6:49 am and sunset at 6:37 pm CDT.

How many hours of sunshine does Louisville have in September?

In September, the average sunshine duration is 9.2h.

What is the UV index intensity in September in Louisville?

In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a moderate health threat from unsafe exposure to Sun's UV rays.
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
Louisville, IL

Average temperature in September - Louisville, IL
  • Average high temperature in September: 78.6°F

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (36.7°F).

  • Average low temperature in September: 59.9°F

The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).

Average pressure in September
Louisville, IL

Average pressure in September - Louisville, IL
  • Average pressure in September: 30.03"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in September
Louisville, IL

Average wind speed in September - Louisville, IL
  • Average wind speed in September: 6.7mph

The windiest months (with the highest average wind speed) are January and February (10.3mph).
The calmest months (with the lowest average wind speed) are July and August (6mph).

Average humidity in September
Louisville, IL

Average humidity in September - Louisville, IL
  • Average humidity in September: 74%

The months with the highest relative humidity are May and July (80%).
The month with the lowest relative humidity is October (70%).

Average rainfall in September
Louisville, IL

Average rainfall in September - Louisville, IL
  • Average rainfall in September: 2.09"

The wettest month (with the highest rainfall) is April (4.88").
The driest months (with the least rainfall) are February and September (2.09").

Average rainfall days in September
Louisville, IL

Average rainfall days in September - Louisville, IL
  • Average rainfall days in September: 13.3 days

The month with the highest number of rainy days is May (19.9 days).
The month with the least rainy days is January (9.3 days).

Average snowfall in September
Louisville, IL

Average snowfall in September - Louisville, IL
  • Average snowfall in September: 0"

The month with the highest snowfall is January (2.05").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Louisville, IL

Average snowfall days in September - Louisville, IL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (7.1 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Louisville, IL

Average daylight in September / Average sunshine in September - Louisville, IL
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in September: 9h and 1min

The month with the most sunshine is June (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

Average sunshine days in September
Louisville, IL

Average sunshine days in September - Louisville, IL
  • Average sunshine days in September: 14.4 days

The month with the most sunshine days is October (17.5 days).
The month with the least sunshine days is May (9 days).

Average UV index in September
Louisville, IL

Average UV index in September - Louisville, IL
  • Average UV index in September: 5

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

Average cloud cover in September
Louisville, IL

Average cloud cover in September - Louisville, IL
  • Average cloud cover in September: 29

The month with the most cloud cover is January (Cloud cover 52).
The month with the least cloud cover is June (Cloud cover 28).

Average visibility in September
Louisville, IL

Average visibility in September - Louisville, IL
  • 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).

Louisville, Illinois, USA

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