Climate and monthly weather forecast
Rio, IL

Weather in January

January, like December, is another subzero cold winter month in Rio, Illinois, with temperature in the range of an average high of 29.5°F (-1.4°C) and an average low of 17.4°F (-8.1°C). With an average high-temperature of 29.5°F (-1.4°C) and an average low-temperature of 17.4°F (-8.1°C), January is the coldest month. Weather in January »

Weather in February

The last month of the winter, February, is a wintry month in Rio, Illinois, with an average temperature fluctuating between 34.7°F (1.5°C) and 21.2°F (-6°C). In February, the average high-temperature is practically the same as in January - a cold 34.7°F (1.5°C). Weather in February »

Weather in March

March, the first month of the spring in Rio, is a frosty month, with an average temperature varying between 48°F (8.9°C) and 32.9°F (0.5°C). In Rio, the average high-temperature in March increases from a cold 34.7°F (1.5°C) in February to a frosty 48°F (8.9°C). Weather in March »

Weather in April

April in Rio, Illinois, is a mild spring month, with an average temperature fluctuating between 59.9°F (15.5°C) and 43.2°F (6.2°C). In April, the average high-temperature increases from a chilly 48°F (8.9°C) in March to a mild 59.9°F (15.5°C). Weather in April »

Weather in May

The last month of the spring, May, is a pleasant month in Rio, Illinois, with an average temperature varying between 54°F (12.2°C) and 70.7°F (21.5°C). In Rio, the average high-temperature in May increases from a mild 59.9°F (15.5°C) in April to a pleasant 70.7°F (21.5°C). Weather in May »

Weather in June

The first month of the summer, June, is a warm month in Rio, Illinois, with an average temperature fluctuating between 79.2°F (26.2°C) and 62.4°F (16.9°C). In June, the average high-temperature marginally rises from a pleasant 70.7°F (21.5°C) in May to a warm 79.2°F (26.2°C). Weather in June »

Weather in July

July, like June, in Rio, Illinois, is another warm summer month, with temperature in the range of an average high of 81.1°F (27.3°C) and an average low of 64.9°F (18.3°C). With an average high-temperature of 81.1°F (27.3°C) and an average low-temperature of 64.9°F (18.3°C), July is the warmest month. The average heat index in July is estimated at a hot 87.8°F (31°C). Weather in July »

Weather in August

August, the last month of the summer in Rio, is another warm month, with an average temperature ranging between min 63.3°F (17.4°C) and max 80.6°F (27°C). In August, the average high-temperature is essentially the same as in July - a still moderately hot 80.6°F (27°C). Weather in August »

Weather in September

September, the first month of the autumn in Rio, is also a moderately hot month, with an average temperature varying between 56.3°F (13.5°C) and 75.6°F (24.2°C). In September, the average high-temperature is essentially the same as in August - a still warm 75.6°F (24.2°C). Weather in September »

Weather in October

October, the same as September, is another comfortable autumn month in Rio, Illinois, with an average temperature ranging between min 45.7°F (7.6°C) and max 61.5°F (16.4°C). In Rio, the average high-temperature in October decreases from a moderately hot 75.6°F (24.2°C) in September to an enjoyable 61.5°F (16.4°C). Weather in October »

Weather in November

November, the last month of the autumn in Rio, is another chilly month, with temperature in the range of an average high of 47.5°F (8.6°C) and an average low of 33.8°F (1°C). In Rio, the average high-temperature in November decreases from a comfortable 61.5°F (16.4°C) in October to a frosty 47.5°F (8.6°C). Weather in November »

Weather in December

December, the first month of the winter in Rio, is also a wintry month, with an average temperature fluctuating between 24.6°F (-4.1°C) and 35.4°F (1.9°C). In December, the average high-temperature drops from a chilly 47.5°F (8.6°C) in November to a cold 35.4°F (1.9°C). Weather in December »
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FAQ

What is the coldest month in Rio?

January is the coldest month in Rio, Illinois, with an average high-temperature of 29.5°F (-1.4°C) and an average low-temperature of 17.4°F (-8.1°C).

What is the driest month in Rio?

The months with the least rainfall are January and December Rain falls for 4 days and accumulates 0.47" (12mm) of rain.

How many days does it rain in Rio?

Throughout the year, in Rio, Illinois, there are 109.9 rainfall days, and 11.14" (283mm) of precipitation is accumulated.

When does it snow in Rio?

Months with snowfall are January through April, October through December.

When does it snow the most in Rio?

The month with the most snowfall is January, when snow falls for 8.8 days and typically aggregates up to 1.38" (35mm) of snow.

How much does it snow in Rio?

Throughout the year, in Rio, Illinois, there are 28 snowfall days, and 4.53" (115mm) of snow is accumulated.

What is the month with the least sunshine in Rio?

With an average of 4h of sunshine, January has the least sunshine of the year in Rio.

When is Daylight Saving Time (DST) in Rio?

On Sunday, March 13. 2022, at 2:00 am, Daylight Saving Time starts, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 6. 2022, at 2:00 am, and the time zone reverts from CDT to CST.

What is the wettest month in Rio?

May is the month with the most rainfall. Rain falls for 15.2 days and accumulates 1.65" (42mm) of precipitation.

When it does not snow in Rio?

May through September are months without snowfall.

When are the longest days in Rio?

With an average of 15h and 5min of daylight, June has the longest days of the year in Rio.

What month has the most sunshine in Rio?

The month with the most sunshine in Rio is June, with an average of 10.1h of sunshine.

What is the month with the highest UV index in Rio?

June and July, with an average maximum UV index of 6, are months with the highest UV index.

What is the warmest month in Rio?

The warmest month in Rio, Illinois, is July, with an average high-temperature of 81.1°F (27.3°C) and an average low-temperature of 64.9°F (18.3°C).

What is the most humid month in Rio?

With an average relative humidity of 84%, July is the most humid month in Rio, Illinois.

What is the least humid month in Rio?

With an average relative humidity of 72%, October is the least humid month in Rio, Illinois.

What is the month with the shortest days in Rio?

December has the shortest days of the year in Rio, with an average of 9h and 16min of daylight.

What is the month with the lowest UV index in Rio?

The month with the lowest UV index in Rio is December, with an average maximum UV index of 1.

Average pressure
Rio, IL

Average pressure - Rio, IL

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
Rio, IL

Average wind speed - Rio, IL

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 rainfall
Rio, IL

Average rainfall - Rio, IL

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
Rio, IL

Average rainfall days - Rio, IL

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
Rio, IL

Average snowfall - Rio, IL

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
Rio, IL

Average snowfall days - Rio, IL

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 / Average sunshine
Rio, IL

Average daylight / Average sunshine - Rio, IL

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).

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
Rio, IL

Average sunshine days - Rio, IL

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 visibility
Rio, IL

Average visibility - Rio, IL

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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