September weather forecast
Thornton, IL

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Weather in September

September, the first month of the autumn in Thornton, is still a warm month, with an average temperature fluctuating between 58.3°F (14.6°C) and 73.9°F (23.3°C).

Temperature

September's arrival coincides with a soft drop in the average high-temperature, subtly decreasing from August's moderately hot 80.1°F (26.7°C) to a still warm 73.9°F (23.3°C). Thornton, during the month of September, experiences an average low-temperature of 58.3°F (14.6°C).

Humidity

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

Rainfall

In September, in Thornton, the rain falls for 13.4 days. Throughout September, 2.48" (63mm) of precipitation is accumulated. In Thornton, during the entire year, the rain falls for 155.6 days and collects up to 31.3" (795mm) of precipitation.

Snowfall

May through September are months without snowfall in Thornton.

Daylight

In September, the average length of the day is 12h and 28min.
On the first day of September, sunrise is at 6:17 am and sunset at 7:23 pm. On the last day of the month, sunrise is at 6:46 am and sunset at 6:33 pm CDT.

Sunshine

In September, the average sunshine in Thornton is 8.8h.

UV index

The average daily maximum UV index in September in Thornton is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for average individuals.
Note: The UV index of 4 during September leads to these advisories:
Exercise prevention - Warding off sunburn is urged. The solar radiation around mid-day is intense; avoid the Sun and stay safe. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes.
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Frequently asked questions

What are the temperatures in Thornton in September?

In September, the average high-temperature and low-temperature in Thornton are 73.9°F (23.3°C) and 58.3°F (14.6°C) respectively. In July, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, is calculated to be 87.8°F (31°C).

What is the average humidity in September in Thornton?

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

How many days does it rain in September in Thornton?

In Thornton, in September, it is raining for 13.4 days, with typically 2.48" (63mm) of accumulated precipitation.

When it does not snow in Thornton?

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

Does it snow in Thornton in September?

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

How many hours of daylight does Thornton have in September?

The average day length in September in Thornton, Illinois, is 12h and 28min.

What time are sunrise and sunset in September in Thornton?

On the first day of September, sunrise is at 6:17 am and sunset at 7:23 pm. On the last day of the month, sunrise is at 6:46 am and sunset at 6:33 pm CDT.

How long on average sun shines in September in Thornton?

The average sunshine duration in September in Thornton is 8.8h.

How high is the UV index in September in Thornton?

In September, the average daily maximum UV index in Thornton, Illinois, is 4. A UV Index value of 3 to 5 symbolizes a medium hazard to health 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
Thornton, IL

Average temperature in September - Thornton, IL
  • Average high temperature in September: 73.9°F

The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (29.7°F).

  • Average low temperature in September: 58.3°F

The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).

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Average pressure in September
Thornton, IL

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

The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

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Average wind speed in September
Thornton, IL

Average wind speed in September - Thornton, IL
  • Average wind speed in September: 7.3mph

The windiest month (with the highest average wind speed) is January (10.2mph).
The calmest month (with the lowest average wind speed) is August (6.3mph).

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Average humidity in September
Thornton, IL

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

The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (73%).

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Average rainfall in September
Thornton, IL

Average rainfall in September - Thornton, IL
  • Average rainfall in September: 2.48"

The wettest month (with the highest rainfall) is May (4.17").
The driest month (with the least rainfall) is December (1.54").

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Average rainfall days in September
Thornton, IL

Average rainfall days in September - Thornton, IL
  • Average rainfall days in September: 13.4 days

The month with the highest number of rainy days is July (17.6 days).
The month with the least rainy days is February (6.1 days).

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Average snowfall in September
Thornton, IL

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

The month with the highest snowfall is January (4.53").
The months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days in September
Thornton, IL

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

The month with the highest number of snowfall days is January (12.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in September / Average sunshine in September - Thornton, 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 12min).

  • Average sunshine in September: 8h and 5min

The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).

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Average sunshine days in September
Thornton, IL

Average sunshine days in September - Thornton, IL
  • Average sunshine days in September: 14 days

The month with the most sunshine days is November (16.4 days).
The month with the least sunshine days is April (10.2 days).

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Average UV index in September
Thornton, IL

Average UV index in September - Thornton, 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
Thornton, IL

Average cloud cover in September - Thornton, IL
  • Average cloud cover in September: 32

The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is August (Cloud cover 30).

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Average visibility in September
Thornton, IL

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

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

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Thornton, Illinois, USA

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