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Contents
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average pressure
- Average wind speed
- Average humidity
- Average rainfall
- Average rainfall days
- Average snowfall
- Average snowfall days
- Average daylight
- Average sunshine
- Average sunshine days
- Average UV index
- Average cloud cover
- Average visibility
Climate and monthly weather forecast
Weather in January
January, the same as December, in Washington, Illinois, is a freezing cold winter month, with an average temperature ranging between min 18.5°F (-7.5°C) and max 30.6°F (-0.8°C). January, having an average high-temperature of 30.6°F (-0.8°C) and an average low-temperature of 18.5°F (-7.5°C), is the coldest month. Weather in January »
Weather in February
February, the last month of the winter in Washington, is an icy month, with an average temperature ranging between max 35.2°F (1.8°C) and min 22.5°F (-5.3°C). The transition from January to February sees an average high-temperature of an icy 35.2°F (1.8°C), indicating a minor variance from the prior month. Weather in February »
Weather in March
The first month of the spring, March, is a chilly month in Washington, Illinois, with an average temperature varying between 48.6°F (9.2°C) and 33.8°F (1°C). The beginning of March marks a shift in the average high-temperature, moving from February's icy 35.2°F (1.8°C) to a chilly 48.6°F (9.2°C). Weather in March »
Weather in April
April in Washington, Illinois, is a refreshing spring month, with temperature in the range of an average high of 60.4°F (15.8°C) and an average low of 44.2°F (6.8°C). The shift from March to April is marked by an increase in the average high-temperature, moving from a chilly 48.6°F (9.2°C) to a refreshing 60.4°F (15.8°C). Weather in April »
Weather in May
The last month of the spring, May, is a pleasant month in Washington, Illinois, with temperature in the range of an average high of 71.6°F (22°C) and an average low of 54.9°F (12.7°C). The start of May signals an increase in the average high-temperature, moving from a mild 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 an average temperature fluctuating between 79.9°F (26.6°C) and 63.1°F (17.3°C). June's onset is marked by a subtle temperature increase, moving 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, the same as June, is a moderately hot summer month in Washington, Illinois, with temperature in the range of an average high of 81.5°F (27.5°C) and an average low of 64.9°F (18.3°C). In Washington, the month of July registers the highest temperatures, averaging 81.5°F (27.5°C) at the peak and 64.9°F (18.3°C) at the lowest. In July, the average heat index is calculated to be a hot 87.8°F (31°C). Weather in July »
Weather in August
August, the last month of the summer in Washington, is another warm month, with an average temperature fluctuating between 80.6°F (27°C) and 63.3°F (17.4°C). Washington registers an average high-temperature of a still moderately hot 80.6°F (27°C) with the arrival of August, showing minor deviation from the preceding month. Weather in August »
Weather in September
The first month of the autumn, September, is still a warm month in Washington, Illinois, with an average temperature fluctuating between 57.2°F (14°C) and 76.1°F (24.5°C). The advent of September presents an average high-temperature of a still warm 76.1°F (24.5°C), maintaining a close correlation with the preceding month. Weather in September »
Weather in October
October, like September, in Washington, Illinois, is another refreshing autumn month, 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). Welcoming October, Washington observes a shift in the average high-temperature, falling from September's warm 76.1°F (24.5°C) to an enjoyable 62.1°F (16.7°C). Weather in October »
Weather in November
The last month of the autumn, November, is also a frosty month in Washington, Illinois, with temperature in the range of an average high of 47.7°F (8.7°C) and an average low of 34.7°F (1.5°C). A distinct shift in the average high-temperature is signaled in November, moving down from a comfortable 62.1°F (16.7°C) in October to a chilly 47.7°F (8.7°C). Weather in November »
Weather in December
December, the first month of the winter in Washington, is also an icy month, with an average temperature ranging between min 25.9°F (-3.4°C) and max 36.5°F (2.5°C). December brings a decrease in the average high-temperature, falling from November's chilly 47.7°F (8.7°C) to a wintry 36.5°F (2.5°C). Weather in December »
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest time of year in Washington?
January, with an average high of 30.6°F (-0.8°C) and a low of 18.5°F (-7.5°C), signifies the coldest month of the year.
How many days 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?
Months with snowfall in Washington, Illinois, are January through April, November and December.
What is the snowiest month in Washington?
The month with the most snowfall in Washington, Illinois, is January, when snow falls for 10.3 days and typically aggregates up to 2.68" (68mm) of snow.
How many days does it snow in Washington?
In Washington, during the entire year, snow falls for 29.2 days and aggregates up to 9.13" (232mm) of snow.
What is the month with the least sunshine in Washington?
January has the least sunshine of the year in Washington, Illinois, with an average of 3.9h of sunshine.
What is the month with the lowest UV index in Washington?
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index.
When is Daylight Saving Time (DST) in Washington?
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 rainiest month in Washington?
May is the month with the most rainfall. Rain falls for 16.2 days and accumulates 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?
June has the longest days of the year, with an average of 15h and 0min of daylight.
What month has the most sunshine in Washington?
The month with the most sunshine in Washington is June, with an average of 10.2h of sunshine.
What are the months 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.
What month is the hottest in Washington?
Temperature records mark July as the warmest month, with highs averaging 81.5°F (27.5°C) and lows at 64.9°F (18.3°C).
What is the most humid month in Washington?
July is the most humid month, with an average relative humidity of 84%.
What is the least humid month in Washington?
With an average relative humidity of 71%, October is the least humid month in Washington, Illinois.
What is the driest month in Washington?
The month with the least rainfall in Washington, Illinois, is November, when the rain falls for 7.2 days and typically collects 0.94" (24mm) of precipitation.
What is the month with the shortest days in Washington?
The month with the shortest days is December, with an average of 9h and 18min of daylight.
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).
Average pressure
Washington, IL
- Average pressure in January:
30.14"Hg - Average pressure in February:
30.11"Hg - Average pressure in March:
30.08"Hg - Average pressure in April:
29.94"Hg - Average pressure in May:
29.95"Hg - Average pressure in June:
29.91"Hg
- Average pressure in July:
29.97"Hg - Average pressure in August:
29.97"Hg - Average pressure in September:
30.03"Hg - Average pressure in October:
30.02"Hg - Average pressure in November:
30.11"Hg - Average pressure in December:
30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed
Washington, IL
- Average wind speed in January:
10.4mph - Average wind speed in February:
10.4mph - Average wind speed in March:
10.3mph - Average wind speed in April:
10.6mph - Average wind speed in May:
8.9mph - Average wind speed in June:
7.8mph
- Average wind speed in July:
6.6mph - Average wind speed in August:
6.5mph - Average wind speed in September:
7.6mph - Average wind speed in October:
9.4mph - Average wind speed in November:
10.1mph - Average wind speed in December:
9.9mph
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).
Average humidity
Washington, IL
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (71%).
Average rainfall
Washington, IL
- Average rainfall in January:
0.98" - Average rainfall in February:
0.98" - Average rainfall in March:
1.46" - Average rainfall in April:
2.36" - Average rainfall in May:
2.6" - Average rainfall in June:
2.17"
- Average rainfall in July:
1.85" - Average rainfall in August:
1.61" - Average rainfall in September:
1.57" - Average rainfall in October:
1.61" - Average rainfall in November:
0.94" - Average rainfall in December:
0.98"
The wettest month (with the highest rainfall) is May (2.6").
The driest month (with the least rainfall) is November (0.94").
Average rainfall days
Washington, IL
- Average rainfall days in January:
4.4 days - Average rainfall days in February:
4.7 days - Average rainfall days in March:
11.1 days - Average rainfall days in April:
12.8 days - Average rainfall days in May:
16.2 days - Average rainfall days in June:
14.3 days
- Average rainfall days in July:
16.4 days - Average rainfall days in August:
12.9 days - Average rainfall days in September:
11.2 days - Average rainfall days in October:
11 days - Average rainfall days in November:
7.2 days - Average rainfall days in December:
6.1 days
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).
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").
Average snowfall days
Washington, IL
- Average snowfall days in January:
10.3 days - Average snowfall days in February:
7.1 days - Average snowfall days in March:
3.4 days - Average snowfall days in April:
0.7 days - Average snowfall days in May:
0 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
0.2 days - Average snowfall days in November:
2 days - Average snowfall days in December:
5.5 days
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).
Average daylight / Average sunshine
Washington, IL
- Average daylight in January:
9h and 4min - Average daylight in February:
10h and 4min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 2min - Average daylight in May:
14h and 3min - Average daylight in June:
15h and 0min
- Average daylight in July:
14h and 4min - Average daylight in August:
13h and 4min - Average daylight in September:
12h and 3min - Average daylight in October:
11h and 1min - Average daylight in November:
9h and 5min - Average daylight in December:
9h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in January:
3h and 5min - Average sunshine in February:
4h and 1min - Average sunshine in March:
6h and 3min - Average sunshine in April:
8h and 1min - Average sunshine in May:
9h and 0min - Average sunshine in June:
10h and 1min
- Average sunshine in July:
10h and 0min - Average sunshine in August:
9h and 5min - Average sunshine in September:
9h and 1min - Average sunshine in October:
5h and 5min - Average sunshine in November:
5h and 2min - Average sunshine in December:
4h and 2min
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).
Average sunshine days
Washington, IL
- Average sunshine days in January:
18.3 days - Average sunshine days in February:
17.3 days - Average sunshine days in March:
16.4 days - Average sunshine days in April:
14.8 days - Average sunshine days in May:
11.8 days - Average sunshine days in June:
12.7 days
- Average sunshine days in July:
11.4 days - Average sunshine days in August:
15.1 days - Average sunshine days in September:
17.2 days - Average sunshine days in October:
18.1 days - Average sunshine days in November:
19.7 days - Average sunshine days in December:
20.5 days
The month with the most sunshine days is December (20.5 days).
The month with the least sunshine days is July (11.4 days).
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).
Average cloud cover
Washington, IL
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is September (Cloud cover 30).
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).