Climate and monthly weather forecast
Saint Charles, IL

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Weather in January

January, the same as December, in Saint Charles, Illinois, is a freezing cold winter month, with temperature in the range of an average low of 16.2°F (-8.8°C) and an average high of 27.9°F (-2.3°C). January is the coldest month, with an average high-temperature of 27.9°F (-2.3°C) and an average low-temperature of 16.2°F (-8.8°C). Weather in January »

Weather in February

February, the last month of the winter in Saint Charles, is another freezing cold month, with an average temperature fluctuating between 31.8°F (-0.1°C) and 19°F (-7.2°C). Stepping into February, Saint Charles records an average high-temperature of a still freezing cold 31.8°F (-0.1°C), almost consistent with January. Weather in February »

Weather in March

The first month of the spring, March, is a chilly month in Saint Charles, Illinois, with an average temperature fluctuating between 44.8°F (7.1°C) and 30.6°F (-0.8°C). The commencement of March sees a shift in the average high-temperature, moving from a freezing cold 31.8°F (-0.1°C) in February to a chilly 44.8°F (7.1°C). Weather in March »

Weather in April

April is a moderate spring month in Saint Charles, Illinois, with an average temperature fluctuating between 56.1°F (13.4°C) and 40.1°F (4.5°C). Saint Charles's transition into April brings a rise in the average high-temperature, moving from a frosty 44.8°F (7.1°C) in March to a mild 56.1°F (13.4°C). Weather in April »

Weather in May

May, the last month of the spring in Saint Charles, is an agreeable month, with an average temperature ranging between max 68.2°F (20.1°C) and min 51.4°F (10.8°C). With the arrival of May, the average high-temperature transitions from a moderate 56.1°F (13.4°C) in April to an agreeable 68.2°F (20.1°C). Weather in May »

Weather in June

June, the first month of the summer in Saint Charles, is a moderately hot month, with an average temperature varying between 77.5°F (25.3°C) and 60.1°F (15.6°C). The transition to June introduces an increase in the average high-temperature, shifting from a pleasant 68.2°F (20.1°C) in May to a warm 77.5°F (25.3°C). Weather in June »

Weather in July

July, like June, in Saint Charles, Illinois, is a moderately hot summer month, with an average temperature fluctuating between 64.2°F (17.9°C) and 81°F (27.2°C). July stands out as Saint Charles's warmest month, with temperatures ranging between an average high of 81°F (27.2°C) and a low of 64.2°F (17.9°C). For most parts of July, the heat index is evaluated at a tropical 86°F (30°C). Weather in July »

Weather in August

August, the last month of the summer in Saint Charles, is another warm month, with an average temperature ranging between max 79.5°F (26.4°C) and min 62.8°F (17.1°C). Saint Charles notes an average high-temperature of a still warm 79.5°F (26.4°C) in August, displaying minor variation from July. Weather in August »

Weather in September

The first month of the autumn, September, is still a warm month in Saint Charles, Illinois, with an average temperature varying between 73.4°F (23°C) and 56.5°F (13.6°C). The shift from August to September includes a minor decrease in the average high-temperature, lightly dropping from a moderately hot 79.5°F (26.4°C) to a still warm 73.4°F (23°C). Weather in September »

Weather in October

October, like September, is a moderate autumn month in Saint Charles, Illinois, with an average temperature fluctuating between 60.3°F (15.7°C) and 44.8°F (7.1°C). Saint Charles's October weather comes with a decrease in average high-temperatures, moving from a moderately hot 73.4°F (23°C) in September to a mild 60.3°F (15.7°C). Weather in October »

Weather in November

November, the last month of the autumn in Saint Charles, is another chilly month, with an average temperature ranging between max 45.5°F (7.5°C) and min 32.7°F (0.4°C). November's onset brings a clear reduction in the average high-temperature, falling from a moderate 60.3°F (15.7°C) in October to a frosty 45.5°F (7.5°C). Weather in November »

Weather in December

The first month of the winter, December, is also an icy month in Saint Charles, Illinois, with temperature in the range of an average low of 23.5°F (-4.7°C) and an average high of 34.2°F (1.2°C). Setting in of December comes with a decrease in the average high-temperature, moving from a chilly 45.5°F (7.5°C) in November to a wintry 34.2°F (1.2°C). Weather in December »
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What part of the year is the coldest in Saint Charles?

January, with an average high of 27.9°F (-2.3°C) and a low of 16.2°F (-8.8°C), signifies the coldest month of the year in Saint Charles, Illinois.

What are the most humid months in Saint Charles?

January and February, with an average relative humidity of 83%, are most humid months in Saint Charles, Illinois.

How many days does it rain in Saint Charles?

Throughout the year, in Saint Charles, there are 101.9 rainfall days, and 8.58" (218mm) of precipitation is accumulated.

When does it snow in Saint Charles?

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

When does it snow the most in Saint Charles?

January is the month with the most snowfall in Saint Charles. Snow falls for 7.6 days and accumulates 1.14" (29mm) of snow.

How much does it snow in Saint Charles?

Throughout the year, in Saint Charles, Illinois, there are 28.3 snowfall days, and 3.74" (95mm) of snow is accumulated.

What is the month with the least sunshine in Saint Charles?

With an average of 3.7h of sunshine, January has the least sunshine of the year.

What is the month with the lowest UV index in Saint Charles?

January and December, with an average maximum UV index of 1, are months with the lowest UV index in Saint Charles.

When is Daylight Saving Time (DST) in Saint Charles?

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 in Saint Charles?

May is the month with the most rainfall. Rain falls for 12.4 days and accumulates 1.26" (32mm) of precipitation.

When it does not snow in Saint Charles?

In Saint Charles, Illinois, snow does not fall in May through September.

When are the longest days in Saint Charles?

June has the longest days of the year in Saint Charles, Illinois, with an average of 15h and 12min of daylight.

What is the month with the highest UV index in Saint Charles?

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

What month is the hottest in Saint Charles?

July stands out as Saint Charles's warmest month, with an average high-temperature of 81°F (27.2°C) and a low-temperature of 64.2°F (17.9°C).

What month has the most sunshine in Saint Charles?

The month with the most sunshine in Saint Charles, Illinois, is July, with an average of 9.9h of sunshine.

What is the least humid month in Saint Charles?

October is the least humid month, with an average relative humidity of 74%.

What is the driest month in Saint Charles?

The months with the least rainfall in Saint Charles, Illinois, are November and December Rain falls for 5.1 days and accumulates 0.39" (10mm) of rain.

What is the month with the shortest days in Saint Charles?

December has the shortest days of the year in Saint Charles, with an average of 9h and 12min of daylight.

Average temperature
Saint Charles, IL

Average temperature - Saint Charles, IL

The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (27.9°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 (16.2°F).

Average pressure
Saint Charles, IL

Average pressure - Saint Charles, IL

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
Saint Charles, IL

Average wind speed - Saint Charles, IL

The windiest month (with the highest average wind speed) is January (9.9mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).

Average humidity
Saint Charles, IL

Average humidity - Saint Charles, IL

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

Average rainfall
Saint Charles, IL

Average rainfall - Saint Charles, IL

The wettest month (with the highest rainfall) is May (1.26").
The driest months (with the least rainfall) are November and December (0.39").

Average rainfall days
Saint Charles, IL

Average rainfall days - Saint Charles, IL

The month with the highest number of rainy days is May (12.4 days).
The month with the least rainy days is January (3.4 days).

Average snowfall
Saint Charles, IL

Average snowfall - Saint Charles, IL

The month with the highest snowfall is January (1.14").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days
Saint Charles, IL

Average snowfall days - Saint Charles, IL

The month with the highest number of snowfall days is January (7.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight / Average sunshine
Saint Charles, IL

Average daylight / Average sunshine - Saint Charles, IL

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).

The month with the most sunshine is July (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

Average sunshine days
Saint Charles, IL

Average sunshine days - Saint Charles, IL

The month with the most sunshine days is December (22.4 days).
The month with the least sunshine days is June (13.3 days).

Average UV index
Saint Charles, IL

Average UV index - Saint Charles, IL

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

Average visibility
Saint Charles, IL

Average visibility - Saint Charles, 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).

Saint Charles, Illinois, USA

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