September weather forecast
La Prairie, IL

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Weather in September

September, the first month of the autumn in La Prairie, is also a moderately hot month, with an average temperature fluctuating between 77.5°F (25.3°C) and 58.1°F (14.5°C).

Temperature

La Prairie observes a small decrease in the average high-temperature with the arrival of September, falling from August's moderately hot 82.9°F (28.3°C) to a still warm 77.5°F (25.3°C). La Prairie, during the nights of September, experiences an average temperature drop to a moderate 58.1°F (14.5°C).

Humidity

The average relative humidity in September is 75%.

Rainfall

In La Prairie, in September, during 10.4 rainfall days, 2.4" (61mm) of precipitation is typically accumulated. Throughout the year, there are 134.2 rainfall days, and 23.15" (588mm) of precipitation is accumulated.

Snowfall

In La Prairie, Illinois, snow does not fall in May through September.

Daylight

The average length of the day in September in La Prairie is 12h and 26min.
On the first day of September, sunrise is at 6:32 am and sunset at 7:35 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:47 pm CDT.

Sunshine

In La Prairie, the average sunshine in September is 9.4h.

UV index

The average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: A maximum high UV index of 5 in September translates into the following recommendations:
Ensure safety - Recommendations to avert sunburn are presented. It's recommended to limit sun exposure when its radiation is at its peak during midday. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation.
Updated: Aug 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature?

The high-temperature during September is 77.5°F (25.3°C) and the low-temperature is 58.1°F (14.5°C). The average heat index (a.k.a. 'felt air temperature', 'feels like'), which factors the actual air temperature with the relative humidity, in August is estimated at 91.4°F (33°C).

What is the average humidity in September?

The average relative humidity in September is 75%.

How many days does it rain in September?

In La Prairie, during September, the rain falls for 10.4 days and regularly aggregates up to 2.4" (61mm) of precipitation.

When it does not snow?

May through September are months without snowfall.

Does it snow in September?

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

How many hours of daylight does La Prairie have in September?

The average day length in September is 12h and 26min.

When are sunrise and sunset in September?

On the first day of September in La Prairie, sunrise is at 6:32 am and sunset at 7:35 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:47 pm CDT.

How many hours of sunshine does La Prairie have in September?

The average sunshine duration in September is 9.4h.

What is the UV index intensity in September?

The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium hazard to health from 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
La Prairie, IL

Average temperature in September - La Prairie, IL
  • Average high temperature in September: 77.5°F

The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (32.7°F).

  • Average low temperature in September: 58.1°F

The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (20.1°F).

Average pressure in September
La Prairie, IL

Average pressure in September - La Prairie, IL
  • Average pressure in September: 30.02"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
La Prairie, IL

Average wind speed in September - La Prairie, IL
  • Average wind speed in September: 7.2mph

The windiest months (with the highest average wind speed) are January and February (10.3mph).
The calmest month (with the lowest average wind speed) is July (6.4mph).

Average humidity in September
La Prairie, IL

Average humidity in September - La Prairie, IL
  • Average humidity in September: 75%

The months with the highest relative humidity are June and July (81%).
The month with the lowest relative humidity is October (71%).

Average rainfall in September
La Prairie, IL

Average rainfall in September - La Prairie, IL
  • Average rainfall in September: 2.4"

The wettest month (with the highest rainfall) is May (3.35").
The driest months (with the least rainfall) are January and December (1.02").

Average rainfall days in September
La Prairie, IL

Average rainfall days in September - La Prairie, IL
  • Average rainfall days in September: 10.4 days

The month with the highest number of rainy days is May (16.9 days).
The month with the least rainy days is January (5 days).

Average snowfall in September
La Prairie, IL

Average snowfall in September - La Prairie, IL
  • Average snowfall in September: 0"

The month with the highest snowfall is January (2.76").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
La Prairie, IL

Average snowfall days in September - La Prairie, IL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (8.8 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
La Prairie, IL

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

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).

Average sunshine days in September
La Prairie, IL

Average sunshine days in September - La Prairie, IL
  • Average sunshine days in September: 18.1 days

The month with the most sunshine days is December (19.6 days).
The month with the least sunshine days is June (11.1 days).

Average UV index in September
La Prairie, IL

Average UV index in September - La Prairie, IL
  • Average UV index in September: 5

The months with the highest UV index are 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
La Prairie, IL

Average cloud cover in September - La Prairie, IL
  • Average cloud cover in September: 30

The month with the most cloud cover is January (Cloud cover 53).
The month with the least cloud cover is July (Cloud cover 28).

Average visibility in September
La Prairie, IL

Average visibility in September - La Prairie, 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).

La Prairie, Illinois, USA

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