Climate and monthly weather forecast
Charleston, IL

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Weather in January

January, like December, in Charleston, Illinois, is another cold winter month, with an average temperature ranging between min 21.9°F (-5.6°C) and max 34°F (1.1°C). The coldest temperatures occur during January, when averages reach a peak of 34°F (1.1°C) and a low of 21.9°F (-5.6°C). Weather in January »

Weather in February

February, the last month of the winter in Charleston, is also a wintry month, with an average temperature ranging between min 26.1°F (-3.3°C) and max 39°F (3.9°C). Upon the beginning of February, Charleston's high-temperatures register at a still wintry 39°F (3.9°C), closely mirroring the preceding month. Weather in February »

Weather in March

The first month of the spring, March, is a cool month in Charleston, Illinois, with temperature in the range of an average high of 51.1°F (10.6°C) and an average low of 36.1°F (2.3°C). March signals a shift in the average high-temperature, moving from February's cold 39°F (3.9°C) to a cool 51.1°F (10.6°C). Weather in March »

Weather in April

April in Charleston, Illinois, is an enjoyable spring month, with temperature in the range of an average high of 62.2°F (16.8°C) and an average low of 46.2°F (7.9°C). Charleston's weather shows a temperature rise with the arrival of April, moving from a fresh 51.1°F (10.6°C) in March to a comfortable 62.2°F (16.8°C). Weather in April »

Weather in May

The last month of the spring, May, is an agreeable month in Charleston, Illinois, with temperature in the range of an average high of 73°F (22.8°C) and an average low of 56.7°F (13.7°C). Charleston's transition into May is marked by a temperature shift, moving from a comfortable 62.2°F (16.8°C) in April to an agreeable 73°F (22.8°C). Weather in May »

Weather in June

The first month of the summer, June, is a moderately hot month in Charleston, Illinois, with an average temperature fluctuating between 81.1°F (27.3°C) and 64.2°F (17.9°C). The beginning of June marks a minor shift in the average high-temperature, moving from May's pleasant 73°F (22.8°C) to a warm 81.1°F (27.3°C). Weather in June »

Weather in July

July, the same as June, is another warm summer month in Charleston, Illinois, with an average temperature varying between 65.8°F (18.8°C) and 82°F (27.8°C). The month of July sees the highest average temperatures, reaching 82°F (27.8°C) at the peak and 65.8°F (18.8°C) at the low. July's heat index is evaluated at a hot 89.6°F (32°C). Weather in July »

Weather in August

August, the last month of the summer in Charleston, is another warm month, with an average temperature varying between 81.1°F (27.3°C) and 64°F (17.8°C). A minimal variation is noted in Charleston's average high-temperature at the onset of August, reaching a still warm 81.1°F (27.3°C) from July's 82°F (27.8°C). Weather in August »

Weather in September

The first month of the autumn, September, is also a moderately hot month in Charleston, Illinois, with temperature in the range of an average low of 58.5°F (14.7°C) and an average high of 77.2°F (25.1°C). The onset of September brings with it an average high-temperature of a still moderately hot 77.2°F (25.1°C), showing a negligible variation from the month before. Weather in September »

Weather in October

October, the same as September, is another enjoyable autumn month in Charleston, Illinois, with an average temperature ranging between max 63.9°F (17.7°C) and min 48.2°F (9°C). October brings a minor decrease, with the average high-temperature reducing from a warm 77.2°F (25.1°C) in September to a comfortable 63.9°F (17.7°C). Weather in October »

Weather in November

The last month of the autumn, November, is also a frosty month in Charleston, Illinois, with an average temperature ranging between min 36.1°F (2.3°C) and max 49.8°F (9.9°C). The transition into November is accompanied by a temperature decrease, with the average high-temperature shifting from a refreshing 63.9°F (17.7°C) in October to a chilly 49.8°F (9.9°C). Weather in November »

Weather in December

December, the first month of the winter in Charleston, is also an icy month, with an average temperature fluctuating between 28.8°F (-1.8°C) and 39°F (3.9°C). December involves a decrease in temperature, down from a frosty 49.8°F (9.9°C) in November to a wintry 39°F (3.9°C). Weather in December »
Updated: Aug 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest time of year in Charleston?

January, marked by an average high-temperature of 34°F (1.1°C) and a low-temperature of 21.9°F (-5.6°C), is the coldest month.

How much does it rain?

Throughout the year, there are 148 rainfall days, and 25.63" (651mm) of precipitation is accumulated.

When does it snow?

January through April, October through December are months with snowfall in Charleston.

How much does it snow in Charleston?

Throughout the year, there are 26.6 snowfall days, and 7.01" (178mm) of snow is accumulated.

What is the month with the least sunshine?

January has the least sunshine of the year, with an average of 4h of sunshine.

What is the driest month?

The month with the least rainfall is February, when the rain falls for 7.8 days and typically collects 1.3" (33mm) of precipitation.

When is Daylight Saving Time (DST)?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.

What is the wettest month?

The month with the most rainfall is April, when the rain falls for 14.9 days and typically aggregates up to 3.31" (84mm) of precipitation.

When it does not snow?

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

When are the longest days?

June has the longest days of the year, with an average of 14h and 54min of daylight.

What month has the most sunshine?

With an average of 10.3h of sunshine, June has the most sunshine of the year.

When is the highest UV index?

June through August, with an average maximum UV index of 6, are months with the highest UV index in Charleston.

What are the warmest months?

The month of July sees the average highest temperatures in Charleston, reaching 82°F (27.8°C) at the peak and 65.8°F (18.8°C) at the low.

What is the most humid month?

The most humid month is July, with an average relative humidity of 83%.

What is the least humid month?

October is the least humid month, with an average relative humidity of 70%.

What is the snowiest month?

December is the month with the most snowfall. Snow falls for 6 days and accumulates 2.13" (54mm) of snow.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 24min of daylight.

When is the lowest UV index?

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

Average temperature
Charleston, IL

Average temperature - Charleston, IL

The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (34°F).

The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (21.9°F).

Average pressure
Charleston, IL

Average pressure - Charleston, IL

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed
Charleston, IL

Average wind speed - Charleston, IL

The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest month (with the lowest average wind speed) is July (6.2mph).

Average humidity
Charleston, IL

Average humidity - Charleston, IL

The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (70%).

Average rainfall
Charleston, IL

Average rainfall - Charleston, IL

The wettest month (with the highest rainfall) is April (3.31").
The driest month (with the least rainfall) is February (1.3").

Average rainfall days
Charleston, IL

Average rainfall days - Charleston, IL

The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is February (7.8 days).

Average snowfall
Charleston, IL

Average snowfall - Charleston, IL

The month with the highest snowfall is December (2.13").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days
Charleston, IL

Average snowfall days - Charleston, IL

The month with the highest number of snowfall days is January (8.1 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight / Average sunshine
Charleston, IL

Average daylight / Average sunshine - Charleston, IL

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).

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 0min).

Average sunshine days
Charleston, IL

Average sunshine days - Charleston, IL

The month with the most sunshine days is October (18.3 days).
The month with the least sunshine days is July (10.6 days).

Average visibility
Charleston, IL

Average visibility - Charleston, IL

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).

Charleston, Illinois, USA

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