September weather forecast
Exeter, IL

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Weather in September

The first month of the autumn, September, is still a warm month in Exeter, Illinois, with temperature in the range of an average low of 58.8°F (14.9°C) and an average high of 78.1°F (25.6°C).

Temperature

The arrival of September suggests a slight decrease in the average high-temperature, moving from 83.5°F (28.6°C) in August to a still warm 78.1°F (25.6°C). Exeter's temperature lowers to a mean of 58.8°F (14.9°C) during the nights in September.

Humidity

The average relative humidity in September is 74%.

Rainfall

In Exeter, during September, the rain falls for 12.2 days and regularly aggregates up to 2.64" (67mm) of precipitation. Throughout the year, in Exeter, there are 155.4 rainfall days, and 31.69" (805mm) of precipitation is accumulated.

Snowfall

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

Daylight

The average length of the day in September is 12h and 26min.
On the first day of September in Exeter, Illinois, sunrise is at 6:30 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:45 pm CDT.

Sunshine

In Exeter, the average sunshine in September is 9.4h.

UV index

In Exeter, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for the average person.
Note: A typical high UV index of 5 in September suggests the following recommendations:
Guard yourself - Precautionary measures against sun damage are advocated. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures in Exeter?

The high-temperature, in September, in Exeter, is 78.1°F (25.6°C), while the low-temperature averages to 58.8°F (14.9°C). The average heat index (a.k.a. 'felt air temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, in August is calculated to be 91.4°F (33°C).

What is the average humidity in September in Exeter?

The average relative humidity in September in Exeter is 74%.

How many days does it rain in September in Exeter?

In Exeter, in September, it is raining for 12.2 days, with typically 2.64" (67mm) of accumulated precipitation.

When it does not snow in Exeter?

May through September are months without snowfall.

Does it snow in Exeter in September?

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

What is the average length of the day in September in Exeter?

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

What time are sunrise and sunset in September in Exeter?

On the first day of September in Exeter, Illinois, sunrise is at 6:30 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:45 pm CDT.

How long on average sun shines in September in Exeter?

In September, the average sunshine duration in Exeter, Illinois, is 9.4h.

How high is the UV index in September in Exeter?

In September, the average daily maximum UV index in Exeter, Illinois, is 5. A UV Index of 3 to 5 symbolizes a moderate vulnerability 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
Exeter, IL

Average temperature in September - Exeter, IL
  • Average high temperature in September: 78.1°F

The warmest month (with the highest average high temperature) is July (84°F).
The month with the lowest average high temperature is January (33.8°F).

  • Average low temperature in September: 58.8°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (21.6°F).

Average pressure in September
Exeter, IL

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

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Exeter, IL

Average wind speed in September - Exeter, IL
  • Average wind speed in September: 6.8mph

The windiest months (with the highest average wind speed) are January and April (9.9mph).
The calmest month (with the lowest average wind speed) is July (6mph).

Average humidity in September
Exeter, IL

Average humidity in September - Exeter, IL
  • Average humidity in September: 74%

The month with the highest relative humidity is July (82%).
The month with the lowest relative humidity is October (71%).

Average rainfall in September
Exeter, IL

Average rainfall in September - Exeter, IL
  • Average rainfall in September: 2.64"

The wettest month (with the highest rainfall) is May (4.02").
The driest months (with the least rainfall) are January, February and December (1.73").

Average rainfall days in September
Exeter, IL

Average rainfall days in September - Exeter, IL
  • Average rainfall days in September: 12.2 days

The month with the highest number of rainy days is May (18.8 days).
The month with the least rainy days is February (7.2 days).

Average snowfall in September
Exeter, IL

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

The month with the highest snowfall is January (3.46").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Exeter, IL

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

The month with the highest number of snowfall days is January (9.8 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
Exeter, IL

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

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).

Average sunshine days in September
Exeter, IL

Average sunshine days in September - Exeter, IL
  • Average sunshine days in September: 15.4 days

The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is June (8.6 days).

Average UV index in September
Exeter, IL

Average UV index in September - Exeter, IL
  • Average UV index in September: 5

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in September
Exeter, IL

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

The month with the most cloud cover is January (Cloud cover 52).
The months with the least cloud cover are June, July, August and September (Cloud cover 30).

Average visibility in September
Exeter, IL

Average visibility in September - Exeter, 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).

Exeter, Illinois, USA

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