Climate and monthly weather forecastShannon, IL
Climate and monthly weather forecast
Weather in January
January, like December, is another subzero cold winter month in Shannon, Illinois, with an average temperature varying between 25.9°F (-3.4°C) and 13.5°F (-10.3°C). January tends to be the coldest month, with temperatures averaging a daily high of 25.9°F (-3.4°C) and a low of 13.5°F (-10.3°C). Weather in January »Weather in February
The last month of the winter, February, is also a subzero cold month in Shannon, Illinois, with an average temperature ranging between max 29.8°F (-1.2°C) and min 16.9°F (-8.4°C). In February, Shannon experiences a minor shift in meteorological conditions with average high-temperatures marked at a still subzero cold 29.8°F (-1.2°C), closely mirroring the climate in January. Weather in February »Weather in March
The first month of the spring, March, is a frosty month in Shannon, Illinois, with an average temperature varying between 29.7°F (-1.3°C) and 44.2°F (6.8°C). The start of March signals a clear increase in the average high-temperature, soaring from a subzero cold 29.8°F (-1.2°C) in February to a frosty 44.2°F (6.8°C). Weather in March »Weather in April
April in Shannon, Illinois, is a mild spring month, with temperature in the range of an average high of 56.5°F (13.6°C) and an average low of 39.9°F (4.4°C). April signals a shift in the average high-temperature, moving from March's frosty 44.2°F (6.8°C) to a mild 56.5°F (13.6°C). Weather in April »Weather in May
May, the last month of the spring in Shannon, is a pleasant month, with an average temperature fluctuating between 68.5°F (20.3°C) and 51.4°F (10.8°C). With the beginning of May, Shannon's average high-temperature sees an increase, transitioning from a refreshing 56.5°F (13.6°C) in April to a pleasant 68.5°F (20.3°C). Weather in May »Weather in June
The first month of the summer, June, is a moderately hot month in Shannon, Illinois, with an average temperature ranging between min 60.4°F (15.8°C) and max 77.2°F (25.1°C). As May transitions into June, Shannon notices a gentle rise in the average high-temperature, transitioning from a pleasant 68.5°F (20.3°C) to a moderately hot 77.2°F (25.1°C). Weather in June »Weather in July
July, like June, in Shannon, Illinois, is a moderately hot summer month, with an average temperature ranging between min 63.3°F (17.4°C) and max 79.9°F (26.6°C). July is the month when Shannon sees the highest average temperatures, with a high of 79.9°F (26.6°C) and a low of 63.3°F (17.4°C). Weather in July »Weather in August
August, the last month of the summer in Shannon, is another warm month, with an average temperature varying between 60.8°F (16°C) and 78.4°F (25.8°C). The onset of August marks an average high-temperature of a still warm 78.4°F (25.8°C), hardly differing from July's 79.9°F (26.6°C). Weather in August »Weather in September
The first month of the autumn, September, is also an agreeable month in Shannon, Illinois, with an average temperature ranging between max 72.9°F (22.7°C) and min 54.5°F (12.5°C). The transition into September subtly indicates a reduction in the average high-temperature, down to a pleasant 72.9°F (22.7°C) from August's warm 78.4°F (25.8°C). Weather in September »Weather in October
October, like September, is another mild autumn month in Shannon, Illinois, with an average temperature varying between 43.2°F (6.2°C) and 59.4°F (15.2°C). A shift in Shannon's weather is observed as September turns into October, with the average high temperature reducing from an agreeable 72.9°F (22.7°C) to a moderate 59.4°F (15.2°C). Weather in October »Weather in November
The last month of the autumn, November, is another chilly month in Shannon, Illinois, with an average temperature fluctuating between 31.3°F (-0.4°C) and 44.8°F (7.1°C). In Shannon, stepping into November signifies a significant temperature decrement, moving down from October's mild 59.4°F (15.2°C) to a chilly 44.8°F (7.1°C). Weather in November »Weather in December
The first month of the winter, December, is still a cold month in Shannon, Illinois, with an average temperature fluctuating between 22.3°F (-5.4°C) and 32.5°F (0.3°C). December's arrival comes with a decrease in the average high-temperature, moving from a chilly 44.8°F (7.1°C) in November to an icy 32.5°F (0.3°C). Weather in December »Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature
Shannon, IL
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (25.9°F).
The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is January (13.5°F).
Average pressure
Shannon, IL
- Average pressure in January:
30.12"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:
29.96"Hg - Average pressure in August:
29.97"Hg - Average pressure in September:
30.03"Hg - Average pressure in October:
30"Hg - Average pressure in November:
30.09"Hg - Average pressure in December:
30.1"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed
Shannon, IL
- Average wind speed in January:
9.8mph - Average wind speed in February:
9.9mph - Average wind speed in March:
9.8mph - Average wind speed in April:
10.4mph - Average wind speed in May:
8.8mph - Average wind speed in June:
7.6mph
- 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:
9.1mph - Average wind speed in November:
9.8mph - Average wind speed in December:
9.4mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity
Shannon, IL
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (75%).
Average rainfall
Shannon, IL
- Average rainfall in January:
0.71" - Average rainfall in February:
0.71" - Average rainfall in March:
1.1" - Average rainfall in April:
1.85" - Average rainfall in May:
2.76" - Average rainfall in June:
2.48"
- Average rainfall in July:
2.05" - Average rainfall in August:
1.22" - Average rainfall in September:
1.5" - Average rainfall in October:
1.57" - Average rainfall in November:
1.14" - Average rainfall in December:
0.87"
The wettest month (with the highest rainfall) is May (2.76").
The driest months (with the least rainfall) are January and February (0.71").
Average rainfall days
Shannon, IL
- Average rainfall days in January:
4.8 days - Average rainfall days in February:
4.4 days - Average rainfall days in March:
10.6 days - Average rainfall days in April:
14.1 days - Average rainfall days in May:
17.9 days - Average rainfall days in June:
16.4 days
- Average rainfall days in July:
15.4 days - Average rainfall days in August:
12.3 days - Average rainfall days in September:
10.7 days - Average rainfall days in October:
10.8 days - Average rainfall days in November:
7.5 days - Average rainfall days in December:
5.9 days
The month with the highest number of rainy days is May (17.9 days).
The month with the least rainy days is February (4.4 days).
Average snowfall
Shannon, IL
The month with the highest snowfall is January (2.64").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days
Shannon, IL
- Average snowfall days in January:
11.2 days - Average snowfall days in February:
9.3 days - Average snowfall days in March:
5.3 days - Average snowfall days in April:
1.1 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:
0.5 days - Average snowfall days in November:
3.2 days - Average snowfall days in December:
8.6 days
The month with the highest number of snowfall days is January (11.2 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight / Average sunshine
Shannon, IL
- Average daylight in January:
9h and 30min - Average daylight in February:
10h and 36min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 24min - Average daylight in May:
14h and 36min - Average daylight in June:
15h and 12min
- Average daylight in July:
14h and 54min - Average daylight in August:
13h and 48min - Average daylight in September:
12h and 30min - Average daylight in October:
11h and 6min - Average daylight in November:
9h and 48min - Average daylight in December:
9h and 12min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in January:
3h and 42min - Average sunshine in February:
3h and 48min - Average sunshine in March:
6h and 12min - Average sunshine in April:
7h and 30min - Average sunshine in May:
8h and 30min - Average sunshine in June:
9h and 30min
- Average sunshine in July:
9h and 48min - Average sunshine in August:
9h and 42min - Average sunshine in September:
9h and 0min - Average sunshine in October:
5h and 24min - Average sunshine in November:
5h and 6min - Average sunshine in December:
4h and 0min
The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days
Shannon, IL
- Average sunshine days in January:
17.3 days - Average sunshine days in February:
16 days - Average sunshine days in March:
16.7 days - Average sunshine days in April:
13.9 days - Average sunshine days in May:
11.6 days - Average sunshine days in June:
10 days
- Average sunshine days in July:
12.7 days - Average sunshine days in August:
16.6 days - Average sunshine days in September:
17.8 days - Average sunshine days in October:
18.6 days - Average sunshine days in November:
19.7 days - Average sunshine days in December:
18.4 days
The month with the most sunshine days is November (19.7 days).
The month with the least sunshine days is June (10 days).
Average UV index
Shannon, IL
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover
Shannon, IL
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is September (Cloud cover 32).
Average visibility
Shannon, IL
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).





