Climate and monthly weather forecastChatham, IL
Climate and monthly weather forecast
Weather in January
January, the same as December, is an icy winter month in Chatham, Illinois, with temperature in the range of an average high of 33.6°F (0.9°C) and an average low of 21.4°F (-5.9°C). January is the coldest month, with an average high-temperature of 33.6°F (0.9°C) and an average low-temperature of 21.4°F (-5.9°C). Weather in January »Weather in February
The last month of the winter, February, is another cold month in Chatham, Illinois, with temperature in the range of an average low of 25.2°F (-3.8°C) and an average high of 38.3°F (3.5°C). The arrival of February brings an average high-temperature of a still icy 38.3°F (3.5°C), nearly identical to January's 33.6°F (0.9°C). Weather in February »Weather in March
March, the first month of the spring in Chatham, is a cool month, with an average temperature fluctuating between 51.4°F (10.8°C) and 36°F (2.2°C). As Chatham welcomes March, the average high-temperature sees a rise, transitioning from a wintry 38.3°F (3.5°C) in February to a fresh 51.4°F (10.8°C). Weather in March »Weather in April
April is a refreshing spring month in Chatham, Illinois, with an average temperature varying between 63.3°F (17.4°C) and 46.2°F (7.9°C). April's arrival sees a rise in the average high-temperature, jumping from March's fresh 51.4°F (10.8°C) to a refreshing 63.3°F (17.4°C). Weather in April »Weather in May
The last month of the spring, May, is a pleasant month in Chatham, Illinois, with temperature in the range of an average high of 72.9°F (22.7°C) and an average low of 56.1°F (13.4°C). The shift from April to May brings an increase in the average high-temperature, moving from an enjoyable 63.3°F (17.4°C) to a pleasant 72.9°F (22.7°C). Weather in May »Weather in June
The first month of the summer, June, is a warm month in Chatham, Illinois, with an average temperature ranging between max 81.1°F (27.3°C) and min 64.8°F (18.2°C). June marks a minor ascent in the average high-temperature, adjusting from May's agreeable 72.9°F (22.7°C) to a moderately hot 81.1°F (27.3°C). Weather in June »Weather in July
July, like June, in Chatham, Illinois, is a moderately hot summer month, with temperature in the range of an average low of 66.6°F (19.2°C) and an average high of 82.8°F (28.2°C). The warmest period is July, when temperatures fluctuate between an average high of 82.8°F (28.2°C) and a low of 66.6°F (19.2°C). The heat index in July is appraised at a hot 91.4°F (33°C). Weather in July »Weather in August
August, the last month of the summer in Chatham, is also a moderately hot month, with temperature in the range of an average high of 81.9°F (27.7°C) and an average low of 64.8°F (18.2°C). With the onset of August, Chatham's average high-temperature clocks in at a still moderately hot 81.9°F (27.7°C), showing a minor fluctuation from the previous month. Weather in August »Weather in September
The first month of the autumn, September, is also a moderately hot month in Chatham, Illinois, with an average temperature ranging between min 58.8°F (14.9°C) and max 77.5°F (25.3°C). The commencement of September introduces an average high-temperature of a still warm 77.5°F (25.3°C), closely mirroring the preceding month. Weather in September »Weather in October
October, the same as September, is another comfortable autumn month in Chatham, Illinois, with an average temperature ranging between max 64.2°F (17.9°C) and min 48.2°F (9°C). The arrival of October signals a shift in temperature, down from a moderately hot 77.5°F (25.3°C) in September to a refreshing 64.2°F (17.9°C). Weather in October »Weather in November
The last month of the autumn, November, is also a fresh month in Chatham, Illinois, with an average temperature fluctuating between 36.3°F (2.4°C) and 50.2°F (10.1°C). The decrease of average high-temperatures is mild in November, with a decline from a refreshing 64.2°F (17.9°C) in October to a fresh 50.2°F (10.1°C). Weather in November »Weather in December
The first month of the winter, December, is still a cold month in Chatham, Illinois, with an average temperature varying between 38.8°F (3.8°C) and 28.4°F (-2°C). The shift from November to December involves a decrease in the average high-temperature, from a fresh 50.2°F (10.1°C) to a cold 38.8°F (3.8°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
January is the coldest month in Chatham, exhibiting average temperatures of 33.6°F (0.9°C) at the peak and 21.4°F (-5.9°C) at the base.
In Chatham, Illinois, during the entire year, the rain falls for 104.2 days and collects up to 9.29" (236mm) of precipitation.
Months with snowfall in Chatham, Illinois, are January through April, November and December.
Throughout the year, in Chatham, Illinois, there are 18.6 snowfall days, and 2.68" (68mm) of snow is accumulated.
January has the least sunshine of the year in Chatham, Illinois, with an average of 4.2h of sunshine.
The months with the lowest UV index in Chatham, Illinois, are January, February, November and December, with an average maximum UV index of 2.
February is the month with the most snowfall in Chatham. Snow falls for 4.8 days and accumulates 0.91" (23mm) of snow.
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.
May through October are months without snowfall in Chatham, Illinois.
The month with the most rainfall in Chatham is June, when the rain falls for 11.6 days and typically aggregates up to 1.22" (31mm) of precipitation.
June has the longest days of the year in Chatham, with an average of 14h and 54min of daylight.
June has the most sunshine of the year in Chatham, with an average of 10.4h of sunshine.
June through August, with an average maximum UV index of 6, are months with the highest UV index in Chatham, Illinois.
In Chatham, Illinois, the peak average temperatures are observed in July, with a high of 82.8°F (28.2°C) and a low of 66.6°F (19.2°C).
July is the most humid month in Chatham, Illinois, with an average relative humidity of 83%.
The least humid month in Chatham is October, with an average relative humidity of 70%.
The month with the least rainfall is December, when the rain falls for 5.5 days and typically collects 0.43" (11mm) of precipitation.
With an average of 9h and 24min of daylight, December has the shortest days of the year in Chatham, Illinois.
Average temperature
Chatham, IL
The warmest month (with the highest average high temperature) is July (82.8°F).
The month with the lowest average high temperature is January (33.6°F).
The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (21.4°F).
Average pressure
Chatham, 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:
29.91"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:
30.03"Hg - Average pressure in November:
30.12"Hg - Average pressure in December:
30.13"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed
Chatham, IL
- Average wind speed in January:
10.4mph - Average wind speed in February:
10.3mph - Average wind speed in March:
10mph - Average wind speed in April:
10.2mph - Average wind speed in May:
8.5mph - Average wind speed in June:
7.3mph
- Average wind speed in July:
6.1mph - Average wind speed in August:
6.2mph - Average wind speed in September:
7mph - Average wind speed in October:
8.9mph - Average wind speed in November:
9.8mph - Average wind speed in December:
9.8mph
The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest month (with the lowest average wind speed) is July (6.1mph).
Average humidity
Chatham, IL
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (70%).
Average rainfall
Chatham, IL
- Average rainfall in January:
0.63" - Average rainfall in February:
0.55" - Average rainfall in March:
0.71" - Average rainfall in April:
1.06" - Average rainfall in May:
1.06" - Average rainfall in June:
1.22"
- Average rainfall in July:
0.91" - Average rainfall in August:
0.83" - Average rainfall in September:
0.63" - Average rainfall in October:
0.79" - Average rainfall in November:
0.47" - Average rainfall in December:
0.43"
The wettest month (with the highest rainfall) is June (1.22").
The driest month (with the least rainfall) is December (0.43").
Average rainfall days
Chatham, IL
- Average rainfall days in January:
4.4 days - Average rainfall days in February:
5.3 days - Average rainfall days in March:
8.9 days - Average rainfall days in April:
11.3 days - Average rainfall days in May:
12.5 days - Average rainfall days in June:
11.6 days
- Average rainfall days in July:
10.8 days - Average rainfall days in August:
10.5 days - Average rainfall days in September:
9.1 days - Average rainfall days in October:
7.7 days - Average rainfall days in November:
6.6 days - Average rainfall days in December:
5.5 days
The month with the highest number of rainy days is May (12.5 days).
The month with the least rainy days is January (4.4 days).
Average snowfall
Chatham, IL
The month with the highest snowfall is February (0.91").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days
Chatham, IL
- Average snowfall days in January:
5.7 days - Average snowfall days in February:
4.8 days - Average snowfall days in March:
2.3 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:
1.5 days - Average snowfall days in December:
3.9 days
The month with the highest number of snowfall days is January (5.7 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight / Average sunshine
Chatham, IL
- Average daylight in January:
9h and 42min - Average daylight in February:
10h and 42min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 18min - Average daylight in May:
14h and 24min - Average daylight in June:
14h and 54min
- Average daylight in July:
14h and 36min - Average daylight in August:
13h and 42min - Average daylight in September:
12h and 24min - Average daylight in October:
11h and 6min - Average daylight in November:
10h and 0min - Average daylight in December:
9h and 24min
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 24min).
- Average sunshine in January:
4h and 12min - Average sunshine in February:
4h and 30min - Average sunshine in March:
6h and 36min - Average sunshine in April:
8h and 18min - Average sunshine in May:
9h and 18min - Average sunshine in June:
10h and 24min
- Average sunshine in July:
10h and 12min - Average sunshine in August:
9h and 54min - Average sunshine in September:
9h and 18min - Average sunshine in October:
6h and 6min - Average sunshine in November:
5h and 30min - Average sunshine in December:
4h and 48min
The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days
Chatham, IL
- Average sunshine days in January:
22.2 days - Average sunshine days in February:
18.7 days - Average sunshine days in March:
18.6 days - Average sunshine days in April:
16.2 days - Average sunshine days in May:
14.8 days - Average sunshine days in June:
14 days
- Average sunshine days in July:
16 days - Average sunshine days in August:
16.2 days - Average sunshine days in September:
18.5 days - Average sunshine days in October:
21.8 days - Average sunshine days in November:
21.8 days - Average sunshine days in December:
22.6 days
The month with the most sunshine days is December (22.6 days).
The month with the least sunshine days is June (14 days).
Average UV index
Chatham, 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
Chatham, IL
The month with the most cloud cover is January (Cloud cover 54).
The months with the least cloud cover are June and September (Cloud cover 29).
Average visibility
Chatham, 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).
