September weather forecast
Rio, IL

Weather in September

September, the first month of the autumn in Rio, is still a warm month, with an average temperature fluctuating between 56.3°F (13.5°C) and 75.6°F (24.2°C).

Temperature

In September, the average high-temperature is practically the same as in August - a still warm 75.6°F (24.2°C). The average low-temperature, is 56.3°F (13.5°C).

Humidity

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

Rainfall

In Rio, it is raining for 8.7 days, with typically 1.02" (26mm) of accumulated precipitation. Throughout the year, in Rio, there are 109.9 rainfall days, and 11.14" (283mm) of precipitation is accumulated.

Snowfall

May through September are months without snowfall.

Daylight

In September, the average length of the day in Rio is 12h and 28min.
On the first day of the month, sunrise is at 6:28 am and sunset at 7:34 pm. On the last day of September, in Rio, sunrise is at 6:57 am and sunset at 6:45 pm CDT.

Sunshine

In September, the average sunshine is 9.2h.

UV index

The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for ordinary individuals.
Note: The average daily UV index of 4 in September transform into the following instructions:
Take precautions - Protection against sunburn is recommended. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the temperature in September in Rio?

The average high-temperature, in September, in Rio, Illinois, is 75.6°F (24.2°C), while the average low-temperature is 56.3°F (13.5°C). in August, the average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which factors the actual air temperature with the relative humidity, is computed to be 86°F (30°C).

What is the average humidity in September in Rio?

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

How much does it rain in Rio in September?

In Rio, Illinois, during September, the rain falls for 8.7 days and regularly aggregates up to 1.02" (26mm) of precipitation.

When it does not snow in Rio?

May through September are months without snowfall.

Does it snow in Rio in September?

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

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

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

When is the sunrise / sunset in September in Rio?

On the first day of September in Rio, sunrise is at 6:28 am and sunset at 7:34 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:45 pm CDT.

How many hours of sunshine does Rio have in September?

In September, the average sunshine duration in Rio, Illinois, is 9.2h.

How high is the UV index in September in Rio?

In September, the average daily maximum UV index in Rio, Illinois, is 4. 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 sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Rio, IL

Average temperature in September - Rio, IL
  • Average high temperature in September: 75.6°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 (29.5°F).

  • Average low temperature in September: 56.3°F

The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (17.4°F).

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Average pressure in September
Rio, IL

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

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in September
Rio, IL

Average wind speed in September - Rio, IL
  • Average wind speed in September: 7.9mph

The windiest month (with the highest average wind speed) is April (10.8mph).
The calmest months (with the lowest average wind speed) are July and August (6.8mph).

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Average humidity in September
Rio, IL

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

The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (72%).

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Average rainfall in September
Rio, IL

Average rainfall in September - Rio, IL
  • Average rainfall in September: 1.02"

The wettest month (with the highest rainfall) is May (1.65").
The driest months (with the least rainfall) are January and December (0.47").

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Average rainfall days in September
Rio, IL

Average rainfall days in September - Rio, IL
  • Average rainfall days in September: 8.7 days

The month with the highest number of rainy days is May (15.2 days).
The month with the least rainy days is February (3.9 days).

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Average snowfall in September
Rio, IL

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

The month with the highest snowfall is January (1.38").
The months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days in September
Rio, IL

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

The month with the highest number of snowfall days is January (8.8 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

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

Average daylight in September / Average sunshine in September - Rio, IL
  • Average daylight in September: 12h and 28min

The month with the longest days is June (Average daylight: 15h and 5min).
The month with the shortest days is December (Average daylight: 9h and 16min).

  • Average sunshine in September: 9h and 12min

The month with the most sunshine is June (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).

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Average sunshine days in September
Rio, IL

Average sunshine days in September - Rio, IL
  • Average sunshine days in September: 18.4 days

The month with the most sunshine days is December (21.6 days).
The month with the least sunshine days is June (12.4 days).

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Average UV index in September
Rio, IL

Average UV index in September - Rio, 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
Rio, IL

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

The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is September (Cloud cover 30).

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Average visibility in September
Rio, IL

Average visibility in September - Rio, 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).

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