Climate and monthly weather forecast
Mattoon, IL

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Weather in January

January, like December, in Mattoon, Illinois, is another cold winter month, with an average temperature fluctuating between 21.9°F (-5.6°C) and 34°F (1.1°C). Temperature records mark January as the coldest month, with highs averaging 34°F (1.1°C) and lows at 21.9°F (-5.6°C). Weather in January »

Weather in February

February, the last month of the winter in Mattoon, is another cold month, with an average temperature varying between 39°F (3.9°C) and 26.1°F (-3.3°C). February ushers in an average high-temperature of a still icy 39°F (3.9°C), aligning closely with the preceding month. Weather in February »

Weather in March

March, the first month of the spring in Mattoon, is a cool month, with an average temperature fluctuating between 51.1°F (10.6°C) and 36.1°F (2.3°C). The rise of average high-temperatures is seen in March, with an increase from an icy 39°F (3.9°C) in February to a cool 51.1°F (10.6°C). Weather in March »

Weather in April

April is a refreshing spring month in Mattoon, Illinois, with an average temperature fluctuating between 62.2°F (16.8°C) and 46.2°F (7.9°C). With the beginning of April, Mattoon's average high-temperature sees an increase, transitioning from a cool 51.1°F (10.6°C) in March to a comfortable 62.2°F (16.8°C). Weather in April »

Weather in May

May, the last month of the spring in Mattoon, is a pleasant month, with an average temperature fluctuating between 73°F (22.8°C) and 56.7°F (13.7°C). May's arrival is marked by an increase in the average high-temperature, moving from a refreshing 62.2°F (16.8°C) in April to an agreeable 73°F (22.8°C). Weather in May »

Weather in June

June, the first month of the summer in Mattoon, is a moderately hot month, with an average temperature fluctuating between 64.2°F (17.9°C) and 81.1°F (27.3°C). June's arrival coincides with a subtle temperature rise, moving from May's pleasant 73°F (22.8°C) to a moderately hot 81.1°F (27.3°C). Weather in June »

Weather in July

July, like June, in Mattoon, Illinois, is a moderately hot summer month, with an average temperature ranging between min 65.8°F (18.8°C) and max 82°F (27.8°C). July stands out as Mattoon's warmest month, with temperatures ranging between an average high of 82°F (27.8°C) and a low of 65.8°F (18.8°C). July's average heat index is calculated to be a tropical 89.6°F (32°C). Weather in July »

Weather in August

August, the last month of the summer in Mattoon, is also a moderately hot month, with an average temperature ranging between max 81.1°F (27.3°C) and min 64°F (17.8°C). The advent of August signifies a minor shift to an average high-temperature of a still warm 81.1°F (27.3°C), aligning closely with July. Weather in August »

Weather in September

September, the first month of the autumn in Mattoon, is also a moderately hot month, with an average temperature fluctuating between 58.5°F (14.7°C) and 77.2°F (25.1°C). September brings a marginal elevation to a still moderately hot 77.2°F (25.1°C) from August's 81.1°F (27.3°C) in Mattoon's average high-temperatures. Weather in September »

Weather in October

October, like September, in Mattoon, Illinois, is another comfortable autumn month, with an average temperature varying between 48.2°F (9°C) and 63.9°F (17.7°C). With the onset of October, Mattoon's average high-temperature adjusts, receding from September's warm 77.2°F (25.1°C) to an enjoyable 63.9°F (17.7°C). Weather in October »

Weather in November

The last month of the autumn, November, is another chilly month in Mattoon, Illinois, with an average temperature varying between 36.1°F (2.3°C) and 49.8°F (9.9°C). The arrival of November signals a shift in temperature, down from a comfortable 63.9°F (17.7°C) in October to a frosty 49.8°F (9.9°C). Weather in November »

Weather in December

The first month of the winter, December, is still a cold month in Mattoon, Illinois, with an average temperature varying between 28.8°F (-1.8°C) and 39°F (3.9°C). With the onset of December, Mattoon experiences a modest temperature adjustment, with the average high-temperature receding from a frosty 49.8°F (9.9°C) in November to a wintry 39°F (3.9°C). Weather in December »

Frequently asked questions

What time of the year is the coldest?

In Mattoon, January is the coldest month, with temperatures averaging a high of 34°F (1.1°C) and a low of 21.9°F (-5.6°C).

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 in Mattoon?

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

How many days does it snow in Mattoon?

In Mattoon, during the entire year, snow falls for 26.6 days and aggregates up to 7.01" (178mm) of snow.

What is the month with the least sunshine?

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

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 Mattoon?

May through September are months without snowfall.

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?

June has the most sunshine of the year in Mattoon, with an average of 10.3h of sunshine.

What is the month with the highest UV index?

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

What month is the hottest?

July, known for its average high temperature of 82°F (27.8°C) and an average low temperature of 65.8°F (18.8°C), is the warmest month.

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?

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

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.

What is the month with the lowest UV index?

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

Average pressure
Mattoon, IL

Average pressure - Mattoon, 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
Mattoon, IL

Average wind speed - Mattoon, 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
Mattoon, IL

Average humidity - Mattoon, IL

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

Average rainfall
Mattoon, IL

Average rainfall - Mattoon, 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
Mattoon, IL

Average rainfall days - Mattoon, 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
Mattoon, IL

Average snowfall - Mattoon, 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
Mattoon, IL

Average snowfall days - Mattoon, 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
Mattoon, IL

Average daylight / Average sunshine - Mattoon, 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
Mattoon, IL

Average sunshine days - Mattoon, 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
Mattoon, IL

Average visibility - Mattoon, 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).

Mattoon, Illinois, USA

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