Climate and monthly weather forecast
Harrisburg, IL

Weather in January

January, the same as December, is another cold winter month in Harrisburg, Illinois, with an average temperature ranging between max 39.7°F (4.3°C) and min 26.2°F (-3.2°C). The coldest month is January, with an average high-temperature of 39.7°F (4.3°C) and an average low-temperature of 26.2°F (-3.2°C). Weather in January »

Weather in February

February, the last month of the winter in Harrisburg, is a frosty month, with an average temperature ranging between max 44.1°F (6.7°C) and min 30.2°F (-1°C). In Harrisburg, the average high-temperature in February is relatively the same as in January - a frosty 44.1°F (6.7°C). Weather in February »

Weather in March

The first month of the spring, March, is a cool month in Harrisburg, Illinois, with an average temperature varying between 55°F (12.8°C) and 39.2°F (4°C). In Harrisburg, the average high-temperature in March rises from a chilly 44.1°F (6.7°C) in February to a cool 55°F (12.8°C). Weather in March »

Weather in April

April is a comfortable spring month in Harrisburg, Illinois, with an average temperature fluctuating between 66.4°F (19.1°C) and 48.7°F (9.3°C). In April, the average high-temperature rises from a cool 55°F (12.8°C) in March to an enjoyable 66.4°F (19.1°C). Weather in April »

Weather in May

The last month of the spring, May, is a moderately hot month in Harrisburg, Illinois, with an average temperature varying between 75.6°F (24.2°C) and 58.1°F (14.5°C). In Harrisburg, the average high-temperature in May rises from a comfortable 66.4°F (19.1°C) in April to a moderately hot 75.6°F (24.2°C). Weather in May »

Weather in June

The first month of the summer, June, is also a moderately hot month in Harrisburg, Illinois, with temperature in the range of an average low of 66.2°F (19°C) and an average high of 84.7°F (29.3°C). In June, the average high-temperature increases from a moderately hot 75.6°F (24.2°C) in May to a still warm 84.7°F (29.3°C). Weather in June »

Weather in July

July in Harrisburg, Illinois, is a tropical summer month, with an average temperature varying between 87.3°F (30.7°C) and 68.5°F (20.3°C). July is the warmest month, with an average high-temperature of 87.3°F (30.7°C) and an average low-temperature of 68.5°F (20.3°C). The average heat index in July is appraised at a very hot 102°F (38.9°C). Weather in July »

Weather in August

August, the last month of the summer in Harrisburg, is also a moderately hot month, with an average temperature varying between 85.6°F (29.8°C) and 66°F (18.9°C). In Harrisburg, the average high-temperature in August is almost the same as in July - a moderately hot 85.6°F (29.8°C). Weather in August »

Weather in September

September, the first month of the autumn in Harrisburg, is still a warm month, with an average temperature ranging between min 60.4°F (15.8°C) and max 80.8°F (27.1°C). In September, the average high-temperature is essentially the same as in August - a still moderately hot 80.8°F (27.1°C). Weather in September »

Weather in October

October, the same as September, is another comfortable autumn month in Harrisburg, Illinois, with an average temperature fluctuating between 49.3°F (9.6°C) and 67.8°F (19.9°C). In Harrisburg, Illinois, the average high-temperature in October drops from a warm 80.8°F (27.1°C) in September to an enjoyable 67.8°F (19.9°C). Weather in October »

Weather in November

The last month of the autumn, November, is another cool month in Harrisburg, Illinois, with temperature in the range of an average high of 53.8°F (12.1°C) and an average low of 38.7°F (3.7°C). In Harrisburg, the average high-temperature in November decreases from a comfortable 67.8°F (19.9°C) in October to a fresh 53.8°F (12.1°C). Weather in November »

Weather in December

The first month of the winter, December, is also a frosty month in Harrisburg, Illinois, with an average temperature ranging between max 44.1°F (6.7°C) and min 32.4°F (0.2°C). In December, the average high-temperature decreases from a cool 53.8°F (12.1°C) in November to a frosty 44.1°F (6.7°C). Weather in December »
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FAQ

What is the coldest month in Harrisburg?

January is the coldest month in Harrisburg, with an average high-temperature of 39.7°F (4.3°C) and an average low-temperature of 26.2°F (-3.2°C).

How much does it rain in Harrisburg?

Throughout the year, in Harrisburg, there are 158.6 rainfall days, and 36.02" (915mm) of precipitation is accumulated.

When does it snow in Harrisburg?

Months with snowfall in Harrisburg, Illinois, are January through April, October through December.

What is the snowiest month in Harrisburg?

The month with the most snowfall in Harrisburg, Illinois, is January, when snow falls for 5.3 days and typically aggregates up to 1.73" (44mm) of snow.

How much does it snow in Harrisburg?

Throughout the year, in Harrisburg, there are 17.7 snowfall days, and 6.57" (167mm) of snow is accumulated.

What is the month with the least sunshine in Harrisburg?

The month with the least sunshine in Harrisburg is January, with an average of 4.6h of sunshine.

What are the months with the lowest UV index in Harrisburg?

The months with the lowest UV index in Harrisburg are January, February and December, with an average maximum UV index of 2.

When is Daylight Saving Time (DST) in Harrisburg?

On Sunday, March 13. 2022, at 2:00 am, Daylight Saving Time starts in Harrisburg, Illinois, 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 rainiest month in Harrisburg?

The month with the most rainfall in Harrisburg is April, when the rain falls for 16.6 days and typically aggregates up to 4.8" (122mm) of precipitation.

What is the most humid month in Harrisburg?

May is the most humid month in Harrisburg, Illinois, with an average relative humidity of 79%.

When it does not snow in Harrisburg?

May through September are months without snowfall in Harrisburg.

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

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

When are the longest days in Harrisburg?

June has the longest days of the year, with an average of 14h and 44min of daylight.

What month has the most sunshine in Harrisburg?

With an average of 10.6h of sunshine, June has the most sunshine of the year in Harrisburg, Illinois.

What is the warmest month in Harrisburg?

With an average high-temperature of 87.3°F (30.7°C) and an average low-temperature of 68.5°F (20.3°C), July is the warmest month.

What is the driest month in Harrisburg?

The month with the least rainfall in Harrisburg, Illinois, is September, when the rain falls for 10.5 days and typically collects 1.57" (40mm) of precipitation.

What is the least humid month in Harrisburg?

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

What is the month with the shortest days in Harrisburg?

December has the shortest days of the year in Harrisburg, with an average of 9h and 36min of daylight.

Average temperature
Harrisburg, IL

Average temperature - Harrisburg, IL

The warmest month (with the highest average high temperature) is July (87.3°F).
The month with the lowest average high temperature is January (39.7°F).

The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (26.2°F).

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Average pressure
Harrisburg, IL

Average pressure - Harrisburg, IL

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

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Average wind speed
Harrisburg, IL

Average wind speed - Harrisburg, IL

The windiest months (with the highest average wind speed) are January and February (9.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.8mph).

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Average rainfall
Harrisburg, IL

Average rainfall - Harrisburg, IL

The wettest month (with the highest rainfall) is April (4.8").
The driest month (with the least rainfall) is September (1.57").

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Average rainfall days
Harrisburg, IL

Average rainfall days - Harrisburg, IL

The month with the highest number of rainy days is May (18.5 days).
The month with the least rainy days is November (9.7 days).

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Average snowfall
Harrisburg, IL

Average snowfall - Harrisburg, IL

The month with the highest snowfall is January (1.73").
The months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days
Harrisburg, IL

Average snowfall days - Harrisburg, IL

The month with the highest number of snowfall days is January (5.3 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
Harrisburg, IL

Average daylight / Average sunshine - Harrisburg, IL

The month with the longest days is June (Average daylight: 14h and 44min).
The month with the shortest days is December (Average daylight: 9h and 36min).

The month with the most sunshine is June (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).

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Average sunshine days
Harrisburg, IL

Average sunshine days - Harrisburg, IL

The month with the most sunshine days is October (19.5 days).
The month with the least sunshine days is May (9.9 days).

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Average UV index
Harrisburg, IL

Average UV index - Harrisburg, IL

The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).

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Average cloud cover
Harrisburg, IL

Average cloud cover - Harrisburg, IL

The months with the most cloud cover are January and February (Cloud cover 51).
The months with the least cloud cover are June and September (Cloud cover 28).

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Average visibility
Harrisburg, IL

Average visibility - Harrisburg, IL

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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