September weather forecast
East Alton, IL

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Weather in September

The first month of the autumn, September, is still a warm month in East Alton, Illinois, with an average temperature fluctuating between 59.4°F (15.2°C) and 78.6°F (25.9°C).

Temperature

The shift from August to September includes a small decrease in the average high-temperature, from a warm 84°F (28.9°C) to a still moderately hot 78.6°F (25.9°C). East Alton, in the month of September, anticipates a consistent average low-temperature of 59.4°F (15.2°C).

Humidity

In September, the average relative humidity is 75%.

Rainfall

In September, in East Alton, the rain falls for 11.8 days. Throughout September, 1.69" (43mm) of precipitation is accumulated. Throughout the year, there are 138 rainfall days, and 23.9" (607mm) of precipitation is accumulated.

Snowfall

May through October are months without snowfall in East Alton.

Daylight

The average length of the day in September in East Alton is 12h and 26min.
On the first day of the month, sunrise is at 6:30 am and sunset at 7:30 pm. On the last day of September, sunrise is at 6:56 am and sunset at 6:44 pm CDT.

Sunshine

The average sunshine in September in East Alton is 9.3h.

UV index

In East Alton, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for the average person.
Note: In September, a daily maximum UV index of 5 leads to the following instructions:
Act with care - Obligation to protect against skin and eye damage is highlighted. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
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Frequently asked questions

What are the temperatures in East Alton in September?

The high-temperature, in September, in East Alton, is 78.6°F (25.9°C), while the low-temperature averages to 59.4°F (15.2°C). The average heat index (a.k.a. 'real feel', 'apparent temperature'), which takes the relative humidity and factors it into the air temperature reading, in August is computed to be 93.2°F (34°C).

What is the average humidity in September in East Alton?

In September, the average relative humidity in East Alton is 75%.

How many days does it rain in September in East Alton?

In September, the rain falls for 11.8 days. Throughout September, 1.69" (43mm) of precipitation is accumulated.

When it does not snow in East Alton?

May through October are months without snowfall in East Alton.

What is the average length of the day in September in East Alton?

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

When are sunrise and sunset in September in East Alton?

In September, on the first day of the month, sunrise is at 6:30 am and sunset at 7:30 pm. On the last day of the month, in East Alton, Illinois, sunrise is at 6:56 am and sunset at 6:44 pm CDT.

How many hours of sunshine does East Alton have in September?

In East Alton, Illinois, the average sunshine duration in September is 9.3h.

How high is the UV index in September in East Alton?

The average daily maximum UV index in September in East Alton, Illinois, is 5. A UV Index value of 3 to 5 symbolizes a moderate vulnerability 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
East Alton, IL

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

The warmest month (with the highest average high temperature) is July (85.3°F).
The month with the lowest average high temperature is January (36.1°F).

  • Average low temperature in September: 59.4°F

The month with the highest average low temperature is July (67.6°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).

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Average pressure in September
East Alton, IL

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

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

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Average wind speed in September
East Alton, IL

Average wind speed in September - East Alton, IL
  • Average wind speed in September: 6.3mph

The windiest months (with the highest average wind speed) are January and February (9.6mph).
The calmest month (with the lowest average wind speed) is July (5.7mph).

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Average humidity in September
East Alton, IL

Average humidity in September - East Alton, IL
  • Average humidity in September: 75%

The month with the highest relative humidity is July (80%).
The month with the lowest relative humidity is October (71%).

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Average rainfall in September
East Alton, IL

Average rainfall in September - East Alton, IL
  • Average rainfall in September: 1.69"

The wettest month (with the highest rainfall) is May (3.07").
The driest month (with the least rainfall) is February (1.14").

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Average rainfall days in September
East Alton, IL

Average rainfall days in September - East Alton, IL
  • Average rainfall days in September: 11.8 days

The month with the highest number of rainy days is May (16.6 days).
The month with the least rainy days is January (5.6 days).

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Average snowfall in September
East Alton, IL

Average snowfall in September - East Alton, IL
  • Average snowfall in September: 0"

The month with the highest snowfall is February (1.61").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days in September
East Alton, IL

Average snowfall days in September - East Alton, IL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (6 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
East Alton, IL

Average daylight in September / Average sunshine in September - East Alton, 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 2min

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

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Average sunshine days in September
East Alton, IL

Average sunshine days in September - East Alton, IL
  • Average sunshine days in September: 15.7 days

The month with the most sunshine days is December (20.4 days).
The month with the least sunshine days is July (12.3 days).

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Average UV index in September
East Alton, IL

Average UV index in September - East Alton, 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).

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Average cloud cover in September
East Alton, IL

Average cloud cover in September - East Alton, IL
  • Average cloud cover in September: 30

The month with the most cloud cover is January (Cloud cover 51).
The months with the least cloud cover are June, July and August (Cloud cover 29).

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Average visibility in September
East Alton, IL

Average visibility in September - East Alton, 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).

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East Alton, Illinois, USA

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