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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, like December, in Williamson, Illinois, is another cold winter month, with an average temperature ranging between min 22.6°F (-5.2°C) and max 35.6°F (2°C). In Williamson, the lowest temperatures are generally noted in January, averaging a high of 35.6°F (2°C) and a low of 22.6°F (-5.2°C). Weather in January »
Weather in February
The last month of the winter, February, is also an icy month in Williamson, Illinois, with an average temperature varying between 40.6°F (4.8°C) and 26.4°F (-3.1°C). The ushering in of February brings an average high-temperature of a still wintry 40.6°F (4.8°C), closely mirroring the 35.6°F (2°C) of January. Weather in February »
Weather in March
March, the first month of the spring in Williamson, is a fresh month, with an average temperature varying between 36.9°F (2.7°C) and 52.3°F (11.3°C). In Williamson, stepping into March brings a temperature increase, moving up from February's icy 40.6°F (4.8°C) to a cool 52.3°F (11.3°C). Weather in March »
Weather in April
April in Williamson, Illinois, is a comfortable spring month, with an average temperature fluctuating between 63.9°F (17.7°C) and 46.6°F (8.1°C). The onset of April marks an increase in the average high-temperature, moving from a cool 52.3°F (11.3°C) in March to a refreshing 63.9°F (17.7°C). Weather in April »
Weather in May
The last month of the spring, May, is a moderately hot month in Williamson, Illinois, with an average temperature ranging between min 56.7°F (13.7°C) and max 73.9°F (23.3°C). The beginning of May marks a shift in the average high-temperature, moving from April's refreshing 63.9°F (17.7°C) to a moderately hot 73.9°F (23.3°C). Weather in May »
Weather in June
June, the first month of the summer in Williamson, is also a moderately hot month, with an average temperature ranging between min 65.5°F (18.6°C) and max 82.2°F (27.9°C). Williamson's transition into June brings a slight rise in the average high-temperature, moving from a moderately hot 73.9°F (23.3°C) in May to a still warm 82.2°F (27.9°C). Weather in June »
Weather in July
July, like June, in Williamson, Illinois, is a moderately hot summer month, with an average temperature fluctuating between 84.2°F (29°C) and 67.5°F (19.7°C). In Williamson, the peak temperatures are generally noted in July, averaging a high of 84.2°F (29°C) and a low of 67.5°F (19.7°C). The average heat index in July is estimated at a torrid 95°F (35°C). Weather in July »
Weather in August
The last month of the summer, August, is also a moderately hot month in Williamson, Illinois, with an average temperature ranging between min 65.5°F (18.6°C) and max 82.9°F (28.3°C). Williamson's average high-temperature in August sits at a still warm 82.9°F (28.3°C), showing little difference from the previous month. Weather in August »
Weather in September
September, the first month of the autumn in Williamson, is still a warm month, with an average temperature varying between 59.4°F (15.2°C) and 77.9°F (25.5°C). The shift to September signals an average high-temperature of a still moderately hot 77.9°F (25.5°C), subtly varied from August's 82.9°F (28.3°C). Weather in September »
Weather in October
October, like September, in Williamson, Illinois, is another comfortable autumn month, with an average temperature varying between 48.4°F (9.1°C) and 65.3°F (18.5°C). Welcoming October, Williamson observes a shift in the average high-temperature, falling from September's moderately hot 77.9°F (25.5°C) to an enjoyable 65.3°F (18.5°C). Weather in October »
Weather in November
November, the last month of the autumn in Williamson, is another cool month, with an average temperature ranging between min 36.9°F (2.7°C) and max 51.6°F (10.9°C). With the beginning of November, the average high-temperature shows a decrease, transitioning from an enjoyable 65.3°F (18.5°C) in October to a cool 51.6°F (10.9°C). Weather in November »
Weather in December
December, the first month of the winter in Williamson, is also an icy month, with an average temperature ranging between max 40.3°F (4.6°C) and min 29.1°F (-1.6°C). Williamson's transition into December involves a shift in temperature, receding from a fresh 51.6°F (10.9°C) in November to an icy 40.3°F (4.6°C). Weather in December »
[Resources]Frequently asked questions
What month is the coldest in Williamson?
In Williamson, January registers the lowest temperatures, averaging 35.6°F (2°C) at the peak and 22.6°F (-5.2°C) at the lowest.
How many days does it rain in Williamson?
In Williamson, Illinois, during the entire year, the rain falls for 121.4 days and collects up to 14.72" (374mm) of precipitation.
When does it snow in Williamson?
Months with snowfall in Williamson, Illinois, are January through March, November and December.
How much does it snow in Williamson?
In Williamson, during the entire year, snow falls for 19.8 days and aggregates up to 2.91" (74mm) of snow.
What is the month with the least sunshine in Williamson?
With an average of 4.4h of sunshine, January has the least sunshine of the year.
What are the months with the lowest UV index in Williamson?
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2.
What is the driest month in Williamson?
The month with the least rainfall is February, when the rain falls for 5.9 days and typically collects 0.67" (17mm) of precipitation.
When is Daylight Saving Time (DST) in Williamson?
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Williamson, 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.
When it does not snow in Williamson?
In Williamson, Illinois, snow does not fall in April through October.
What is the rainiest month in Williamson?
The month with the most rainfall in Williamson, Illinois, is June, when the rain falls for 13.4 days and typically aggregates up to 1.89" (48mm) of precipitation.
When are the longest days in Williamson?
With an average of 14h and 54min of daylight, June has the longest days of the year.
What is the month with the most sunshine in Williamson?
June and July, with an average of 10.3h of sunshine, are months with the most sunshine in Williamson, Illinois.
When is the highest UV index in Williamson?
June through August, with an average maximum UV index of 6, are months with the highest UV index in Williamson.
What part of the year is the hottest in Williamson?
Temperature readings reach their annual highs in July, averaging 84.2°F (29°C) and a minimum average of 67.5°F (19.7°C).
What is the most humid month in Williamson?
With an average relative humidity of 81%, July is the most humid month.
What is the least humid month in Williamson?
With an average relative humidity of 71%, October is the least humid month in Williamson, Illinois.
What is the snowiest month in Williamson?
The month with the most snowfall in Williamson is December, when snow falls for 3.8 days and typically aggregates up to 0.98" (25mm) of snow.
What is the month with the shortest days in Williamson?
With an average of 9h and 30min of daylight, December has the shortest days of the year.
Average temperature
Williamson, IL
The warmest month (with the highest average high temperature) is July (84.2°F).
The month with the lowest average high temperature is January (35.6°F).
The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (22.6°F).
Average pressure
Williamson, IL
- Average pressure in January:
30.16"Hg - Average pressure in February:
30.12"Hg - Average pressure in March:
30.07"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:
30.02"Hg - Average pressure in October:
30.03"Hg - Average pressure in November:
30.12"Hg - Average pressure in December:
30.13"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed
Williamson, IL
- Average wind speed in January:
10mph - Average wind speed in February:
9.9mph - Average wind speed in March:
9.6mph - Average wind speed in April:
9.6mph - Average wind speed in May:
7.8mph - Average wind speed in June:
6.8mph
- Average wind speed in July:
5.8mph - Average wind speed in August:
5.9mph - Average wind speed in September:
6.4mph - Average wind speed in October:
8.5mph - Average wind speed in November:
9.2mph - Average wind speed in December:
9.3mph
The windiest month (with the highest average wind speed) is January (10mph).
The calmest month (with the lowest average wind speed) is July (5.8mph).
Average humidity
Williamson, IL
The month with the highest relative humidity is July (81%).
The month with the lowest relative humidity is October (71%).
Average rainfall
Williamson, IL
- Average rainfall in January:
1.02" - Average rainfall in February:
0.67" - Average rainfall in March:
1.02" - Average rainfall in April:
1.57" - Average rainfall in May:
1.81" - Average rainfall in June:
1.89"
The wettest month (with the highest rainfall) is June (1.89").
The driest month (with the least rainfall) is February (0.67").
Average rainfall days
Williamson, IL
- Average rainfall days in January:
5.8 days - Average rainfall days in February:
5.9 days - Average rainfall days in March:
10.7 days - Average rainfall days in April:
12.5 days - Average rainfall days in May:
13.9 days - Average rainfall days in June:
13.4 days
- Average rainfall days in July:
14 days - Average rainfall days in August:
12.1 days - Average rainfall days in September:
10.4 days - Average rainfall days in October:
8.5 days - Average rainfall days in November:
7.5 days - Average rainfall days in December:
6.7 days
The month with the highest number of rainy days is July (14 days).
The month with the least rainy days is January (5.8 days).
Average snowfall
Williamson, IL
The month with the highest snowfall is December (0.98").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days
Williamson, IL
- Average snowfall days in January:
6.3 days - Average snowfall days in February:
5.5 days - Average snowfall days in March:
2.5 days - Average snowfall days in April:
0.3 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:
0.1 days - Average snowfall days in November:
1.3 days - Average snowfall days in December:
3.8 days
The month with the highest number of snowfall days is January (6.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight / Average sunshine
Williamson, IL
- Average daylight in January:
9h and 5min - Average daylight in February:
10h and 5min - 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:
14h and 5min
- 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 1min - Average daylight in December:
9h and 3min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in January:
4h and 2min - Average sunshine in February:
4h and 3min - Average sunshine in March:
6h and 2min - Average sunshine in April:
8h and 2min - Average sunshine in May:
9h and 2min - Average sunshine in June:
10h and 2min
- Average sunshine in July:
10h and 2min - Average sunshine in August:
9h and 5min - Average sunshine in September:
9h and 2min - Average sunshine in October:
6h and 1min - Average sunshine in November:
5h and 3min - Average sunshine in December:
4h and 5min
The months with the most sunshine are June and July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).
Average sunshine days
Williamson, IL
- Average sunshine days in January:
20.9 days - Average sunshine days in February:
17.2 days - Average sunshine days in March:
17 days - Average sunshine days in April:
14.6 days - Average sunshine days in May:
13.6 days - Average sunshine days in June:
12.8 days
- Average sunshine days in July:
12.5 days - Average sunshine days in August:
15.3 days - Average sunshine days in September:
17.2 days - Average sunshine days in October:
19.7 days - Average sunshine days in November:
20.4 days - Average sunshine days in December:
20.5 days
The month with the most sunshine days is January (20.9 days).
The month with the least sunshine days is July (12.5 days).
Average UV index
Williamson, 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
Williamson, IL
The month with the most cloud cover is January (Cloud cover 52).
The months with the least cloud cover are June, July, August and September (Cloud cover 29).
Average visibility
Williamson, 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).
Williamson, Illinois, USA
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