September weather forecast
Somerset, IL

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Somerset, Illinois, with an average temperature varying between 60.4°F (15.8°C) and 80.8°F (27.1°C).

Temperature

Somerset's September average high-temperature settles at a still moderately hot 80.8°F (27.1°C), showing a near match with the preceding month. In Somerset, the nighttime temperature averages to a mild 60.4°F (15.8°C) during September.

Heat index

In September, the heat index is calculated to be 84.2°F (29°C). Prolonged activity during exposure might result in a state of fatigue and cause heat cramps.
Heat index evaluations are typically in the context of light winds and shaded environments. When exposed to the direct sun, the heat index may augment by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'real feel', unifies temperature and humidity readings to offer a comprehensive feel of warmth. The effect is experienced differently by individuals, hinging on unique characteristics such as body mass, stature, and level of activity. Direct exposure to sun rays can potentially augment the heat sensation, elevating the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Younglings are generally more in peril than adults due to their reduced perspiration. Coupled with a larger skin surface relative to their tiny bodies and greater heat production because of their activity, they become more at risk.

Humidity

The average relative humidity in September is 73%.

Rainfall

September is the month with the least rainfall. Rain falls for 10.5 days and accumulates 1.57" (40mm) of precipitation.

Snowfall

In Somerset, snow does not fall in May through September.

Daylight

In September, the average length of the day in Somerset is 12h and 25min.
On the first day of the month, sunrise is at 6:24 am and sunset at 7:22 pm. On the last day of September, sunrise is at 6:49 am and sunset at 6:37 pm CDT.

Sunshine

The average sunshine in September is 9.2h.

UV index

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: A maximum high UV index of 5 in September translates into the following recommendations:
Take heed. Individuals of lighter complexion can be burned in less than half an hour. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat.
Updated: Jun 21, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Somerset in September?

In Somerset, in September, the average high-temperature is 80.8°F (27.1°C), and the average low-temperature is 60.4°F (15.8°C). In September, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which calculates the temperature value influenced by the moisture in the air, is calculated to be 84.2°F (29°C).

What is the average humidity in September?

In Somerset, the average relative humidity in September is 73%.

What is the driest month?

The month with the least rainfall is September, when the rain falls for 10.5 days and typically collects 1.57" (40mm) of precipitation.

How many days does it rain in September?

In September, the rain falls for 10.5 days. Throughout September, 1.57" (40mm) of precipitation is accumulated.

When it does not snow in Somerset?

May through September are months without snowfall.

Does it snow in September?

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

What is the average length of the day in September?

The average day length in September is 12h and 25min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:24 am and sunset at 7:22 pm. On the last day of the month, sunrise is at 6:49 am and sunset at 6:37 pm CDT.

How many hours of sunshine does Somerset have in September?

The average sunshine duration in September is 9.2h.

What is the UV index reading in September?

In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate health threat 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
Somerset, IL

Average temperature in September - Somerset, IL
  • Average high temperature in September: 80.8°F

The warmest month (with the highest average high temperature) is July (87.3°F).
The month with the lowest average high temperature is January (39.7°F).

  • Average low temperature in September: 60.4°F

The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (26.2°F).

Average pressure in September
Somerset, IL

Average pressure in September - Somerset, IL
  • Average pressure in September: 30.03"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
Somerset, IL

Average wind speed in September - Somerset, IL
  • Average wind speed in September: 6.4mph

The windiest months (with the highest average wind speed) are January and February (9.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.8mph).

Average humidity in September
Somerset, IL

Average humidity in September - Somerset, IL
  • Average humidity in September: 73%

The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (70%).

Average rainfall in September
Somerset, IL

Average rainfall in September - Somerset, IL
  • Average rainfall in September: 1.57"

The wettest month (with the highest rainfall) is April (4.8").
The driest month (with the least rainfall) is September (1.57").

Average rainfall days in September
Somerset, IL

Average rainfall days in September - Somerset, IL
  • Average rainfall days in September: 10.5 days

The month with the highest number of rainy days is May (18.5 days).
The month with the least rainy days is November (9.7 days).

Average snowfall in September
Somerset, IL

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

The month with the highest snowfall is January (1.73").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Somerset, IL

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

The month with the highest number of snowfall days is January (5.3 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
Somerset, IL

Average daylight in September / Average sunshine in September - Somerset, 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 36min).

  • Average sunshine in September: 9h and 1min

The month with the most sunshine is June (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).

Average sunshine days in September
Somerset, IL

Average sunshine days in September - Somerset, IL
  • Average sunshine days in September: 17.1 days

The month with the most sunshine days is October (19.5 days).
The month with the least sunshine days is May (9.9 days).

Average UV index in September
Somerset, IL

Average UV index in September - Somerset, 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
Somerset, IL

Average cloud cover in September - Somerset, IL
  • Average cloud cover in September: 28

The months with the most cloud cover are January and February (Cloud cover 51).
The months with the least cloud cover are June and September (Cloud cover 28).

Average visibility in September
Somerset, IL

Average visibility in September - Somerset, 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).

Somerset, Illinois, USA

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