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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
Weather in January
January, the same as December, is a wintry winter month in Illiopolis, Illinois, with an average temperature varying between 32.5°F (0.3°C) and 20.5°F (-6.4°C). With its high average temperature of 32.5°F (0.3°C) and a low of 20.5°F (-6.4°C), January is regarded as the coldest month. Weather in January »
Weather in February
The last month of the winter, February, is another cold month in Illiopolis, Illinois, with temperature in the range of an average low of 24.6°F (-4.1°C) and an average high of 37.6°F (3.1°C). The advent of February observes an average high-temperature of a still icy 37.6°F (3.1°C), nearly identical to January's 32.5°F (0.3°C). Weather in February »
Weather in March
March, the first month of the spring in Illiopolis, is a fresh month, with temperature in the range of an average low of 35.2°F (1.8°C) and an average high of 50°F (10°C). The start of March brings a shift in the average high-temperature, increasing from February's icy 37.6°F (3.1°C) to a cool 50°F (10°C). Weather in March »
Weather in April
April is an enjoyable spring month in Illiopolis, Illinois, with an average temperature fluctuating between 62.2°F (16.8°C) and 45.9°F (7.7°C). The start of April is characterized by an increase in the average high-temperature, transitioning from a cool 50°F (10°C) in March to a refreshing 62.2°F (16.8°C). Weather in April »
Weather in May
May, the last month of the spring in Illiopolis, is a pleasant month, with an average temperature fluctuating between 56.5°F (13.6°C) and 72.9°F (22.7°C). May's arrival sees a rise in the average high-temperature, jumping from April's comfortable 62.2°F (16.8°C) to an agreeable 72.9°F (22.7°C). Weather in May »
Weather in June
June, the first month of the summer in Illiopolis, is a warm month, with an average temperature fluctuating between 80.6°F (27°C) and 63.9°F (17.7°C). In Illiopolis, the average high-temperature in June slightly increases from a pleasant 72.9°F (22.7°C) in May to a moderately hot 80.6°F (27°C). Weather in June »
Weather in July
July, the same as June, is another warm summer month in Illiopolis, Illinois, with temperature in the range of an average low of 65.7°F (18.7°C) and an average high of 82°F (27.8°C). The month of July sees the highest average temperatures, reaching 82°F (27.8°C) at the peak and 65.7°F (18.7°C) at the low. The heat index in July is computed to be a tropical 89.6°F (32°C). Weather in July »
Weather in August
The last month of the summer, August, is another warm month in Illiopolis, Illinois, with temperature in the range of an average low of 63.9°F (17.7°C) and an average high of 81.3°F (27.4°C). The commencement of August records an average high-temperature of a still warm 81.3°F (27.4°C), barely varying from July's 82°F (27.8°C). Weather in August »
Weather in September
September, the first month of the autumn in Illiopolis, is still a warm month, with temperature in the range of an average low of 58.5°F (14.7°C) and an average high of 77°F (25°C). September's weather records an average high-temperature of a still moderately hot 77°F (25°C), showing little deviation from August. Weather in September »
Weather in October
October, like September, in Illiopolis, Illinois, is another comfortable autumn month, with an average temperature ranging between max 63.9°F (17.7°C) and min 47.8°F (8.8°C). In Illiopolis, the average high-temperature in October drops from a moderately hot 77°F (25°C) in September to an enjoyable 63.9°F (17.7°C). Weather in October »
Weather in November
The last month of the autumn, November, is also a frosty month in Illiopolis, Illinois, with temperature in the range of an average low of 36°F (2.2°C) and an average high of 49.8°F (9.9°C). With November's arrival, Illiopolis, Illinois, sees a decrease in average high-temperatures, moving from a refreshing 63.9°F (17.7°C) in October to a chilly 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 Illiopolis, Illinois, with an average temperature fluctuating between 27.5°F (-2.5°C) and 38.3°F (3.5°C). The shift from November to December corresponds with a decrease in the average high-temperature, down to a wintry 38.3°F (3.5°C) from a frosty 49.8°F (9.9°C). Weather in December »
Updated: Jun 27, 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?
The month of January sees the average lowest temperatures, reaching 32.5°F (0.3°C) at the peak and 20.5°F (-6.4°C) at the low.
How many days does it rain?
In Illiopolis, during the entire year, the rain falls for 141.8 days and collects up to 22.24" (565mm) of precipitation.
When does it snow?
Months with snowfall are January through April, November and December.
When does it snow the most?
January is the month with the most snowfall in Illiopolis, Illinois. Snow falls for 9.4 days and accumulates 2.24" (57mm) of snow.
How many days does it snow?
In Illiopolis, during the entire year, snow falls for 29.7 days and aggregates up to 7.13" (181mm) of snow.
What is the month with the least sunshine?
The month with the least sunshine is January, with an average of 4h of sunshine.
What is the month with the lowest UV index?
The month with the lowest UV index is January, with an average maximum UV index of 1.
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 rainiest month in Illiopolis?
May is the month with the most rainfall in Illiopolis. Rain falls for 17 days and accumulates 2.68" (68mm) of precipitation.
When it does not snow?
In Illiopolis, snow does not fall in May through October.
When are the longest days?
With an average of 15h and 0min of daylight, June has the longest days of the year.
What month has the most sunshine?
June has the most sunshine of the year, with an average of 10.2h of sunshine.
What are the months 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 time of the year is the hottest in Illiopolis?
Illiopolis's warmest weather arrives in July, when temperatures average a high of 82°F (27.8°C) and a low of 65.7°F (18.7°C).
What is the most humid month?
With an average relative humidity of 84%, July is the most humid month.
What is the least humid month?
October is the least humid month in Illiopolis, with an average relative humidity of 70%.
What is the driest month?
December is the month with the least rainfall. Rain falls for 8.3 days and accumulates 1.1" (28mm) of precipitation.
What is the month with the shortest days?
With an average of 9h and 24min of daylight, December has the shortest days of the year in Illiopolis.
Average temperature
Illiopolis, IL
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (32.5°F).
The month with the highest average low temperature is July (65.7°F).
The coldest month (with the lowest average low temperature) is January (20.5°F).
Average pressure
Illiopolis, IL
- Average pressure in January:
30.15"Hg - Average pressure in February:
30.12"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:
29.92"Hg
- Average pressure in July:
29.97"Hg - Average pressure in August:
29.98"Hg - Average pressure in September:
30.03"Hg - Average pressure in October:
30.02"Hg - Average pressure in November:
30.12"Hg - Average pressure in December:
30.12"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed
Illiopolis, 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:
8.8mph - Average wind speed in June:
7.5mph
- Average wind speed in July:
6.3mph - Average wind speed in August:
6.3mph - Average wind speed in September:
7.3mph - Average wind speed in October:
9.1mph - Average wind speed in November:
9.8mph - Average wind speed in December:
9.8mph
The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).
Average humidity
Illiopolis, IL
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (70%).
Average rainfall
Illiopolis, IL
- Average rainfall in January:
1.42" - Average rainfall in February:
1.18" - Average rainfall in March:
1.61" - Average rainfall in April:
2.44" - Average rainfall in May:
2.68" - Average rainfall in June:
2.48"
- Average rainfall in July:
2.05" - Average rainfall in August:
2.13" - Average rainfall in September:
1.81" - Average rainfall in October:
2.01" - Average rainfall in November:
1.34" - Average rainfall in December:
1.1"
The wettest month (with the highest rainfall) is May (2.68").
The driest month (with the least rainfall) is December (1.1").
Average rainfall days
Illiopolis, IL
- Average rainfall days in January:
6.3 days - Average rainfall days in February:
6.3 days - Average rainfall days in March:
11.7 days - Average rainfall days in April:
14.8 days - Average rainfall days in May:
17 days - Average rainfall days in June:
15.8 days
- Average rainfall days in July:
16.3 days - Average rainfall days in August:
14.3 days - Average rainfall days in September:
11.8 days - Average rainfall days in October:
10.6 days - Average rainfall days in November:
8.6 days - Average rainfall days in December:
8.3 days
The month with the highest number of rainy days is May (17 days).
The months with the least rainy days are January and February (6.3 days).
Average snowfall
Illiopolis, IL
The month with the highest snowfall is January (2.24").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days
Illiopolis, IL
- Average snowfall days in January:
9.4 days - Average snowfall days in February:
7.1 days - Average snowfall days in March:
2.9 days - Average snowfall days in April:
0.8 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:
0.1 days - Average snowfall days in October:
0.3 days - Average snowfall days in November:
2.4 days - Average snowfall days in December:
6.7 days
The month with the highest number of snowfall days is January (9.4 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight / Average sunshine
Illiopolis, 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 2min - 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 2min - Average daylight in October:
11h and 1min - Average daylight in November:
10h and 0min - 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 24min).
- Average sunshine in January:
4h and 0min - Average sunshine in February:
4h and 2min - Average sunshine in March:
6h and 2min - Average sunshine in April:
8h and 0min - Average sunshine in May:
9h and 1min - Average sunshine in June:
10h and 1min
- Average sunshine in July:
9h and 5min - Average sunshine in August:
9h and 4min - Average sunshine in September:
9h and 0min - Average sunshine in October:
5h and 5min - Average sunshine in November:
5h and 2min - Average sunshine in December:
4h and 3min
The month with the most sunshine is June (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days
Illiopolis, IL
- Average sunshine days in January:
16.3 days - Average sunshine days in February:
14.7 days - Average sunshine days in March:
15.7 days - Average sunshine days in April:
12.8 days - Average sunshine days in May:
10.8 days - Average sunshine days in June:
11.8 days
- Average sunshine days in July:
10.9 days - Average sunshine days in August:
13.1 days - Average sunshine days in September:
15.8 days - Average sunshine days in October:
18.1 days - Average sunshine days in November:
18.9 days - Average sunshine days in December:
17.1 days
The month with the most sunshine days is November (18.9 days).
The month with the least sunshine days is May (10.8 days).
Average UV index
Illiopolis, IL
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover
Illiopolis, IL
The month with the most cloud cover is January (Cloud cover 57).
The months with the least cloud cover are June and September (Cloud cover 31).
Average visibility
Illiopolis, 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).
Illiopolis, Illinois, USA
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