September weather forecast
Oswego, IL

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Weather in September

The first month of the autumn, September, is still a warm month in Oswego, Illinois, with temperature in the range of an average high of 74.1°F (23.4°C) and an average low of 56.3°F (13.5°C).

Temperature

The average high-temperature in September, at a still moderately hot 74.1°F (23.4°C), reveals a modest deviation from August's 79.3°F (26.3°C). The temperature in Oswego lowers to an average of 56.3°F (13.5°C) during September nights.

Humidity

In September, the average relative humidity is 78%.

Rainfall

In September, the rain falls for 12 days. Throughout September, 1.3" (33mm) of precipitation is accumulated. In Oswego, during the entire year, the rain falls for 133.1 days and collects up to 16.93" (430mm) of precipitation.

Snowfall

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

Daylight

The average length of the day in September is 12h and 28min.
On the first day of the month, sunrise is at 6:20 am and sunset at 7:26 pm. On the last day of September, in Oswego, sunrise is at 6:49 am and sunset at 6:36 pm CDT.

Sunshine

In Oswego, the average sunshine in September is 8.7h.

UV index

In Oswego, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for ordinary individuals.
Note: In September, the maximum UV index of 4 suggests these recommendations:
Adopt protective measures - Suggestions to resist sunburn are offered. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures in Oswego?

The high-temperature during September is 74.1°F (23.4°C) and the low-temperature is 56.3°F (13.5°C). The average heat index (a.k.a. 'real feel', 'apparent temperature'), which represents the influence of relative humidity on air temperature, in July is estimated at 87.8°F (31°C).

What is the average humidity in September in Oswego?

In Oswego, the average relative humidity in September is 78%.

How much does it rain in Oswego in September?

In Oswego, Illinois, in September, it is raining for 12 days, with typically 1.3" (33mm) of accumulated precipitation.

When it does not snow in Oswego?

May through September are months without snowfall.

Does it snow in Oswego in September?

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

How many hours of daylight does Oswego have in September?

In Oswego, Illinois, the average day length in September is 12h and 28min.

When is the sunrise / sunset in September in Oswego?

On the first day of September, sunrise is at 6:20 am and sunset at 7:26 pm. On the last day of the month, sunrise is at 6:49 am and sunset at 6:36 pm CDT.

How many hours of sunshine does Oswego have in September?

The average sunshine duration in September is 8.7h.

What is the UV index reading in September in Oswego?

In September, the average daily maximum UV index in Oswego is 4. 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
Oswego, IL

Average temperature in September - Oswego, IL
  • Average high temperature in September: 74.1°F

The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (28.4°F).

  • Average low temperature in September: 56.3°F

The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (16.7°F).

Average pressure in September
Oswego, IL

Average pressure in September - Oswego, 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).

Average wind speed in September
Oswego, IL

Average wind speed in September - Oswego, IL
  • Average wind speed in September: 7mph

The windiest month (with the highest average wind speed) is April (9.7mph).
The calmest month (with the lowest average wind speed) is August (6mph).

Average humidity in September
Oswego, IL

Average humidity in September - Oswego, IL
  • Average humidity in September: 78%

The months with the highest relative humidity are January, February, July and August (83%).
The month with the lowest relative humidity is October (74%).

Average rainfall in September
Oswego, IL

Average rainfall in September - Oswego, IL
  • Average rainfall in September: 1.3"

The wettest month (with the highest rainfall) is June (2.24").
The driest months (with the least rainfall) are November and December (0.75").

Average rainfall days in September
Oswego, IL

Average rainfall days in September - Oswego, IL
  • Average rainfall days in September: 12 days

The month with the highest number of rainy days is July (16.6 days).
The month with the least rainy days is February (4.3 days).

Average snowfall in September
Oswego, IL

Average snowfall in September - Oswego, 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
Oswego, IL

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

The month with the highest number of snowfall days is January (10.7 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in September / Average sunshine in September - Oswego, IL
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in September: 8h and 4min

The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).

Average sunshine days in September
Oswego, IL

Average sunshine days in September - Oswego, IL
  • Average sunshine days in September: 14.5 days

The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is July (10.2 days).

Average UV index in September
Oswego, IL

Average UV index in September - Oswego, IL
  • Average UV index in September: 4

The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).

Average cloud cover in September
Oswego, IL

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

The month with the most cloud cover is January (Cloud cover 60).
The month with the least cloud cover is September (Cloud cover 32).

Average visibility in September
Oswego, IL

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

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

Oswego, Illinois, USA

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