September weather forecast
Tamms, IL

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Tamms, Illinois, with temperature in the range of an average high of 81.5°F (27.5°C) and an average low of 61.9°F (16.6°C).

Temperature

Tamms transitions into September recording an average high-temperature of a moderately hot 81.5°F (27.5°C), closely aligning with the preceding month's temperature. During the September nights, an average temperature of 61.9°F (16.6°C) is observed.

Heat index

The heat index for September is calculated to be a hot 86°F (30°C). If one sustains activity during exposure, it could lead to a sense of fatigue, with a chance of heat cramps.
Given the heat index, its values are aligned with shaded sites and gentle winds. The heat index values could be amplified by up to 15 Fahrenheit (8 Celsius) degrees in direct sunlight.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', is the result of factoring in humidity to the air temperature, indicating perceived warmth. Factors such as metabolic variations, being pregnant, and physical activity can impact an individual's weather perception. Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are largely significant for babies and toddlers. Young individuals are typically more threatened than adults due to their reduced perspiration. Also, the larger skin surface proportionate to their small bodies and the increased heat from their activities magnify their risk.

Humidity

The average relative humidity in September is 72%.

Rainfall

The month with the least rainfall is September, when the rain falls for 11.4 days and typically collects 1.42" (36mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of September, sunrise is at 6:28 am and sunset at 7:25 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:41 pm CDT.

Sunshine

In Tamms, the average sunshine in September is 9.6h.

UV index

In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV rays for average individuals.
Note: The average daily UV index of 5 in September transforms into the following instructions:
Preventative actions are necessary - Suggestions to safeguard against sun damage are in order. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Updated: Aug 28, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

In September, the average high-temperature and low-temperature are 81.5°F (27.5°C) and 61.9°F (16.6°C) respectively. In September, the average heat index (a.k.a. 'apparent temperature', 'feels like'), 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 September, the average relative humidity is 72%.

What is the driest month?

The month with the least rainfall is September, when the rain falls for 11.4 days and typically collects 1.42" (36mm) of precipitation.

How much does it rain in September?

In September, the rain falls for 11.4 days. Throughout September, 1.42" (36mm) of precipitation is accumulated.

When it does not snow?

May through September are months without snowfall.

Does it snow in September?

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

How many hours of daylight does Tamms have in September?

In Tamms, the average day length in September is 12h and 25min.

When are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:28 am and sunset at 7:25 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:41 pm CDT.

How many hours of sunshine does Tamms have in September?

The average sunshine duration in September is 9.6h.

What is the UV index intensity in September?

In Tamms, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate vulnerability 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
Tamms, IL

Average temperature in September - Tamms, IL
  • Average high temperature in September: 81.5°F

The warmest month (with the highest average high temperature) is July (88.2°F).
The month with the lowest average high temperature is January (41.2°F).

  • Average low temperature in September: 61.9°F

The month with the highest average low temperature is July (69.8°F).
The coldest month (with the lowest average low temperature) is January (28.4°F).

Average pressure in September
Tamms, IL

Average pressure in September - Tamms, 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 (29.94"Hg).

Average wind speed in September
Tamms, IL

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

The windiest months (with the highest average wind speed) are January, February and March (9.1mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).

Average humidity in September
Tamms, IL

Average humidity in September - Tamms, IL
  • Average humidity in September: 72%

The months with the highest relative humidity are February, March, May and December (78%).
The month with the lowest relative humidity is October (69%).

Average rainfall in September
Tamms, IL

Average rainfall in September - Tamms, IL
  • Average rainfall in September: 1.42"

The wettest month (with the highest rainfall) is April (4.21").
The driest month (with the least rainfall) is September (1.42").

Average rainfall days in September
Tamms, IL

Average rainfall days in September - Tamms, IL
  • Average rainfall days in September: 11.4 days

The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is January (9.8 days).

Average snowfall in September
Tamms, IL

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

The month with the highest snowfall is February (1.5").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Tamms, IL

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

The month with the highest number of snowfall days is February (3.8 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
Tamms, IL

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

The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 42min).

  • Average sunshine in September: 9h and 4min

The month with the most sunshine is June (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).

Average sunshine days in September
Tamms, IL

Average sunshine days in September - Tamms, IL
  • Average sunshine days in September: 16.5 days

The month with the most sunshine days is October (18.5 days).
The month with the least sunshine days is May (12.3 days).

Average UV index in September
Tamms, IL

Average UV index in September - Tamms, 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 and December (UV index 2).

Average cloud cover in September
Tamms, IL

Average cloud cover in September - Tamms, IL
  • Average cloud cover in September: 27

The month with the most cloud cover is February (Cloud cover 49).
The month with the least cloud cover is June (Cloud cover 26).

Average visibility in September
Tamms, IL

Average visibility in September - Tamms, 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).

Tamms, Illinois, USA

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