Climate and monthly weather forecast
Washington, IL

Weather in January

January, the same as December, in Washington, Illinois, is a freezing cold winter month, with an average temperature fluctuating between 30.6°F (-0.8°C) and 18.5°F (-7.5°C). January is the coldest month, with an average high-temperature of 30.6°F (-0.8°C) and an average low-temperature of 18.5°F (-7.5°C). Weather in January »

Weather in February

The last month of the winter, February, is a wintry month in Washington, Illinois, with an average temperature fluctuating between 22.5°F (-5.3°C) and 35.2°F (1.8°C). In Washington, the average high-temperature in February is relatively the same as in January - a cold 35.2°F (1.8°C). Weather in February »

Weather in March

The first month of the spring, March, is a chilly month in Washington, Illinois, with an average temperature ranging between min 33.8°F (1°C) and max 48.6°F (9.2°C). In March, the average high-temperature rises from a cold 35.2°F (1.8°C) in February to a frosty 48.6°F (9.2°C). Weather in March »

Weather in April

April is a mild spring month in Washington, Illinois, with an average temperature ranging between min 44.2°F (6.8°C) and max 60.4°F (15.8°C). In April, the average high-temperature increases from a chilly 48.6°F (9.2°C) in March to a mild 60.4°F (15.8°C). Weather in April »

Weather in May

The last month of the spring, May, is an agreeable month in Washington, Illinois, with an average temperature varying between 54.9°F (12.7°C) and 71.6°F (22°C). In Washington, the average high-temperature in May increases from a moderate 60.4°F (15.8°C) in April to an agreeable 71.6°F (22°C). Weather in May »

Weather in June

The first month of the summer, June, is a warm month in Washington, Illinois, with temperature in the range of an average high of 79.9°F (26.6°C) and an average low of 63.1°F (17.3°C). In Washington, the average high-temperature in June marginally rises from a pleasant 71.6°F (22°C) in May to a moderately hot 79.9°F (26.6°C). Weather in June »

Weather in July

July, like June, in Washington, Illinois, is a moderately hot summer month, with an average temperature ranging between max 81.5°F (27.5°C) and min 64.9°F (18.3°C). With an average high-temperature of 81.5°F (27.5°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 evaluated at a tropical 87.8°F (31°C). Weather in July »

Weather in August

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

Weather in September

The first month of the autumn, September, is also a moderately hot month in Washington, Illinois, with an average temperature varying between 57.2°F (14°C) and 76.1°F (24.5°C). In Washington, Illinois, the average high-temperature in September is almost the same as in August - a still moderately hot 76.1°F (24.5°C). Weather in September »

Weather in October

October, the same as September, is another enjoyable autumn month in Washington, Illinois, with temperature in the range of an average high of 62.1°F (16.7°C) and an average low of 46.6°F (8.1°C). In Washington, the average high-temperature in October drops from a moderately hot 76.1°F (24.5°C) in September to a comfortable 62.1°F (16.7°C). Weather in October »

Weather in November

November, the last month of the autumn in Washington, is another chilly month, with an average temperature fluctuating between 34.7°F (1.5°C) and 47.7°F (8.7°C). In Washington, the average high-temperature in November plummets from a comfortable 62.1°F (16.7°C) in October to a frosty 47.7°F (8.7°C). Weather in November »

Weather in December

December, the first month of the winter in Washington, is also a wintry month, with an average temperature varying between 25.9°F (-3.4°C) and 36.5°F (2.5°C). In December, the average high-temperature drops from a frosty 47.7°F (8.7°C) in November to a cold 36.5°F (2.5°C). Weather in December »
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FAQ

What is the coldest month in Washington?

With an average high-temperature of 30.6°F (-0.8°C) and an average low-temperature of 18.5°F (-7.5°C), January is the coldest month in Washington.

How much does it rain in Washington?

Throughout the year, in Washington, there are 128.3 rainfall days, and 19.13" (486mm) of precipitation is accumulated.

When does it snow in Washington?

January through April, November and December are months with snowfall in Washington, Illinois.

What is the snowiest month in Washington?

The month with the most snowfall in Washington is January, when snow falls for 10.3 days and typically aggregates up to 2.68" (68mm) of snow.

How much does it snow in Washington?

Throughout the year, there are 29.2 snowfall days, and 9.13" (232mm) of snow is accumulated.

What is the month with the least sunshine in Washington?

January has the least sunshine of the year in Washington, with an average of 3.9h of sunshine.

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

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

When is Daylight Saving Time (DST) in Washington?

On Sunday, March 12. 2023, at 2:00 am, Daylight Saving Time starts in Washington, Illinois, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 5. 2023, at 2:00 am, and the time zone reverts from CDT to CST.

What is the wettest month in Washington?

The month with the most rainfall is May, when the rain falls for 16.2 days and typically aggregates up to 2.6" (66mm) of precipitation.

When it does not snow in Washington?

May through October are months without snowfall.

When are the longest days in Washington?

The month with the longest days in Washington is June, with an average of 15h and 2min of daylight.

What month has the most sunshine in Washington?

The month with the most sunshine in Washington, Illinois, is June, with an average of 10.2h of sunshine.

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

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

What is the warmest month in Washington?

The warmest month is July, with an average high-temperature of 81.5°F (27.5°C) and an average low-temperature of 64.9°F (18.3°C).

What is the most humid month in Washington?

The most humid month is July, with an average relative humidity of 84%.

What is the least humid month in Washington?

October is the least humid month in Washington, Illinois, with an average relative humidity of 71%.

What is the driest month in Washington?

November is the month with the least rainfall. Rain falls for 7.2 days and accumulates 0.94" (24mm) of precipitation.

What is the month with the shortest days in Washington?

The month with the shortest days in Washington, Illinois, is December, with an average of 9h and 19min of daylight.

Average temperature
Washington, IL

Average temperature - Washington, IL

The warmest month (with the highest average high temperature) is July (81.5°F).
The month with the lowest average high temperature is January (30.6°F).

The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (18.5°F).

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Average pressure
Washington, IL

Average pressure - Washington, 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
Washington, IL

Average wind speed - Washington, IL

The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).

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Average rainfall
Washington, IL

Average rainfall - Washington, IL

The wettest month (with the highest rainfall) is May (2.6").
The driest month (with the least rainfall) is November (0.94").

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Average rainfall days
Washington, IL

Average rainfall days - Washington, IL

The month with the highest number of rainy days is July (16.4 days).
The month with the least rainy days is January (4.4 days).

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Average snowfall
Washington, IL

Average snowfall - Washington, IL

The month with the highest snowfall is January (2.68").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days
Washington, IL

Average snowfall days - Washington, IL

The month with the highest number of snowfall days is January (10.3 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
Washington, IL

Average daylight / Average sunshine - Washington, IL

The month with the longest days is June (Average daylight: 15h and 2min).
The month with the shortest days is December (Average daylight: 9h and 19min).

The month with the most sunshine is June (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).

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Average sunshine days
Washington, IL

Average sunshine days - Washington, IL

The month with the most sunshine days is December (20.5 days).
The month with the least sunshine days is July (11.4 days).

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Average UV index
Washington, IL

Average UV index - Washington, 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, February, November and December (UV index 2).

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Average visibility
Washington, IL

Average visibility - Washington, 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).

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