September weather forecast
Henderson, IL

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Weather in September

The first month of the autumn, September, is still a warm month in Henderson, Illinois, with an average temperature ranging between min 56.3°F (13.5°C) and max 75.6°F (24.2°C).

Temperature

The transition into September marks the average high-temperature at a still warm 75.6°F (24.2°C), differing minimally from August's 80.6°F (27°C). Throughout September, Henderson's nights cool down to an average of 56.3°F (13.5°C).

Humidity

In Henderson, the average relative humidity in September is 76%.

Rainfall

In Henderson, during September, the rain falls for 8.7 days and regularly aggregates up to 1.02" (26mm) of precipitation. In Henderson, during the entire year, the rain falls for 109.9 days and collects up to 11.14" (283mm) of precipitation.

Snowfall

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

Daylight

The average length of the day in September is 12h and 27min.
On the first day of the month, sunrise is at 6:28 am and sunset at 7:33 pm. On the last day of September, in Henderson, sunrise is at 6:57 am and sunset at 6:44 pm CDT.

Sunshine

In September, the average sunshine in Henderson, Illinois, is 9.2h.

UV index

In Henderson, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: The average daily UV index of 4 in September transforms into the following instructions:
Exercise prudence. Persons with fair skin could be burned in under 30 minutes. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays.
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Frequently asked questions

What are the temperatures in Henderson in September?

The high-temperature, in September, in Henderson, is 75.6°F (24.2°C), while the low-temperature averages to 56.3°F (13.5°C). In August, the average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which factors the actual air temperature with the relative humidity, is calculated to be 86°F (30°C).

What is the average humidity in September in Henderson?

In September, the average relative humidity is 76%.

How many days does it rain in September in Henderson?

In Henderson, in September, it is raining for 8.7 days, with typically 1.02" (26mm) of accumulated precipitation.

When it does not snow in Henderson?

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

Does it snow in Henderson in September?

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

How many hours of daylight does Henderson have in September?

The average day length in September is 12h and 27min.

When are sunrise and sunset in September in Henderson?

On the first day of September, sunrise is at 6:28 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:44 pm CDT.

How long on average sun shines in September in Henderson?

In September, the average sunshine duration in Henderson, Illinois, is 9.2h.

What is the UV index reading in September in Henderson?

In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents 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
Henderson, IL

Average temperature in September - Henderson, IL
  • Average high temperature in September: 75.6°F

The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (29.5°F).

  • Average low temperature in September: 56.3°F

The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (17.4°F).

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Average pressure in September
Henderson, IL

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

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in September
Henderson, IL

Average wind speed in September - Henderson, IL
  • Average wind speed in September: 7.9mph

The windiest month (with the highest average wind speed) is April (10.8mph).
The calmest months (with the lowest average wind speed) are July and August (6.8mph).

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Average humidity in September
Henderson, IL

Average humidity in September - Henderson, IL
  • Average humidity in September: 76%

The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (72%).

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Average rainfall in September
Henderson, IL

Average rainfall in September - Henderson, IL
  • Average rainfall in September: 1.02"

The wettest month (with the highest rainfall) is May (1.65").
The driest months (with the least rainfall) are January and December (0.47").

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Average rainfall days in September
Henderson, IL

Average rainfall days in September - Henderson, IL
  • Average rainfall days in September: 8.7 days

The month with the highest number of rainy days is May (15.2 days).
The month with the least rainy days is February (3.9 days).

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Average snowfall in September
Henderson, IL

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

The month with the highest snowfall is January (1.38").
The months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days in September
Henderson, IL

Average snowfall days in September - Henderson, 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).

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

Average daylight in September / Average sunshine in September - Henderson, IL
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in September: 9h and 1min

The month with the most sunshine is June (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).

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Average sunshine days in September
Henderson, IL

Average sunshine days in September - Henderson, IL
  • Average sunshine days in September: 18.4 days

The month with the most sunshine days is December (21.6 days).
The month with the least sunshine days is June (12.4 days).

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Average UV index in September
Henderson, IL

Average UV index in September - Henderson, IL
  • Average UV index in September: 4

The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).

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Average cloud cover in September
Henderson, IL

Average cloud cover in September - Henderson, IL
  • Average cloud cover in September: 30

The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is September (Cloud cover 30).

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Average visibility in September
Henderson, IL

Average visibility in September - Henderson, IL
  • Average visibility in September: 6mi

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

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Henderson, Illinois, USA

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