Climate and monthly weather forecastBig Rock, IL
Climate and monthly weather forecast
Weather in January
January, like December, is another subzero cold winter month in Big Rock, Illinois, with an average temperature ranging between min 15.8°F (-9°C) and max 27.9°F (-2.3°C). January, with its average high-temperature of 27.9°F (-2.3°C) and an average low-temperature of 15.8°F (-9°C), holds the record as the coldest month. Weather in January »Weather in February
February, the last month of the winter in Big Rock, is a wintry month, with an average temperature ranging between max 32°F (0°C) and min 19°F (-7.2°C). The advent of February brings an average high-temperature of a wintry 32°F (0°C), exhibiting minor difference from the previous month. Weather in February »Weather in March
March, the first month of the spring in Big Rock, is a chilly month, with an average temperature fluctuating between 45.5°F (7.5°C) and 30.7°F (-0.7°C). As Big Rock transitions into March, the average high-temperature is observed to rise from an icy 32°F (0°C) in February to a frosty 45.5°F (7.5°C). Weather in March »Weather in April
April is a mild spring month in Big Rock, Illinois, with an average temperature ranging between max 57°F (13.9°C) and min 40.1°F (4.5°C). April's arrival coincides with a temperature rise, moving from March's frosty 45.5°F (7.5°C) to a refreshing 57°F (13.9°C). Weather in April »Weather in May
May, the last month of the spring in Big Rock, is a pleasant month, with an average temperature fluctuating between 69.1°F (20.6°C) and 51.8°F (11°C). Big Rock sees a rise in temperature during May, with average high-temperatures transitioning from a mild 57°F (13.9°C) in April to a pleasant 69.1°F (20.6°C). Weather in May »Weather in June
The first month of the summer, June, is a moderately hot month in Big Rock, Illinois, with an average temperature ranging between min 60.6°F (15.9°C) and max 78.1°F (25.6°C). The start of June signals an increase in the average high-temperature, moving from an agreeable 69.1°F (20.6°C) in May to a moderately hot 78.1°F (25.6°C). Weather in June »Weather in July
July, the same as June, is another warm summer month in Big Rock, Illinois, with an average temperature fluctuating between 63.3°F (17.4°C) and 80.6°F (27°C). In Big Rock, the month of July registers the highest temperatures, averaging 80.6°F (27°C) at the peak and 63.3°F (17.4°C) at the lowest. The heat index for July is calculated to be a tropical 86°F (30°C). Weather in July »Weather in August
August, the last month of the summer in Big Rock, is also a moderately hot month, with an average temperature varying between 61.7°F (16.5°C) and 79.2°F (26.2°C). The advent of August brings an average high-temperature of a still warm 79.2°F (26.2°C), almost identical to the preceding month. Weather in August »Weather in September
September, the first month of the autumn in Big Rock, is still a warm month, with an average temperature ranging between min 55.4°F (13°C) and max 73.8°F (23.2°C). The onset of September aligns with a soft reduction in the average high-temperature, gently falling from a warm 79.2°F (26.2°C) in August to a still moderately hot 73.8°F (23.2°C). Weather in September »Weather in October
October, the same as September, in Big Rock, Illinois, is another mild autumn month, with an average temperature ranging between max 60.3°F (15.7°C) and min 44.4°F (6.9°C). The shift from September to October involves a decrease in the average high-temperature, dropping from a warm 73.8°F (23.2°C) to a mild 60.3°F (15.7°C). Weather in October »Weather in November
November, the last month of the autumn in Big Rock, is another chilly month, with an average temperature fluctuating between 32.7°F (0.4°C) and 45.5°F (7.5°C). The shift from October to November brings a noticeable decrease in the average high-temperature, dropping from a mild 60.3°F (15.7°C) to a chilly 45.5°F (7.5°C). Weather in November »Weather in December
December, the first month of the winter in Big Rock, is still a cold month, with temperature in the range of an average low of 23.7°F (-4.6°C) and an average high of 34.2°F (1.2°C). Setting in of December comes with a decrease in the average high-temperature, moving from a frosty 45.5°F (7.5°C) in November to a wintry 34.2°F (1.2°C). Weather in December »Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature
Big Rock, IL
The warmest month (with the highest average high temperature) is July (80.6°F).
The month with the lowest average high temperature is January (27.9°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 (15.8°F).
Average pressure
Big Rock, IL
- Average pressure in January:
30.11"Hg - Average pressure in February:
30.1"Hg - Average pressure in March:
30.09"Hg - Average pressure in April:
29.95"Hg - Average pressure in May:
29.96"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:
30.01"Hg - Average pressure in November:
30.09"Hg - Average pressure in December:
30.1"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed
Big Rock, IL
- Average wind speed in January:
9.8mph - Average wind speed in February:
9.8mph - Average wind speed in March:
9.5mph - Average wind speed in April:
9.8mph - Average wind speed in May:
8.3mph - Average wind speed in June:
7.2mph
- Average wind speed in July:
6.3mph - Average wind speed in August:
6mph - Average wind speed in September:
7mph - Average wind speed in October:
8.6mph - Average wind speed in November:
9.3mph - Average wind speed in December:
9.1mph
The windiest months (with the highest average wind speed) are January, February and April (9.8mph).
The calmest month (with the lowest average wind speed) is August (6mph).
Average humidity
Big Rock, IL
The months with the highest relative humidity are January, July and August (84%).
The month with the lowest relative humidity is October (74%).
Average rainfall
Big Rock, IL
- Average rainfall in January:
1.73" - Average rainfall in February:
1.65" - Average rainfall in March:
1.97" - Average rainfall in April:
3.54" - Average rainfall in May:
4.33" - Average rainfall in June:
3.98"
- Average rainfall in July:
3.15" - Average rainfall in August:
2.4" - Average rainfall in September:
2.28" - Average rainfall in October:
2.72" - Average rainfall in November:
1.65" - Average rainfall in December:
1.57"
The wettest month (with the highest rainfall) is May (4.33").
The driest month (with the least rainfall) is December (1.57").
Average rainfall days
Big Rock, IL
- Average rainfall days in January:
6.5 days - Average rainfall days in February:
6 days - Average rainfall days in March:
12.1 days - Average rainfall days in April:
17.3 days - Average rainfall days in May:
18 days - Average rainfall days in June:
18.1 days
- Average rainfall days in July:
18.2 days - Average rainfall days in August:
15.7 days - Average rainfall days in September:
13 days - Average rainfall days in October:
13.8 days - Average rainfall days in November:
9.9 days - Average rainfall days in December:
7.8 days
The month with the highest number of rainy days is July (18.2 days).
The month with the least rainy days is February (6 days).
Average snowfall
Big Rock, IL
- Average snowfall in January:
4.65" - Average snowfall in February:
3.43" - Average snowfall in March:
1.54" - Average snowfall in April:
1.42" - Average snowfall in May:
0.04" - Average snowfall in June:
0"
The month with the highest snowfall is January (4.65").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days
Big Rock, IL
- Average snowfall days in January:
13.1 days - Average snowfall days in February:
10.4 days - Average snowfall days in March:
6.2 days - Average snowfall days in April:
1.7 days - Average snowfall days in May:
0.2 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:
0.4 days - Average snowfall days in November:
3.5 days - Average snowfall days in December:
9.1 days
The month with the highest number of snowfall days is January (13.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight / Average sunshine
Big Rock, IL
- Average daylight in January:
9h and 36min - 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 54min - Average sunshine in March:
6h and 6min - 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 30min - Average sunshine in August:
9h and 36min - Average sunshine in September:
8h and 36min - Average sunshine in October:
5h and 30min - Average sunshine in November:
5h and 6min - Average sunshine in December:
4h and 6min
The month with the most sunshine is August (Average sunshine: 9h and 36min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days
Big Rock, IL
- Average sunshine days in January:
14.3 days - Average sunshine days in February:
12.5 days - Average sunshine days in March:
13.9 days - Average sunshine days in April:
10.3 days - Average sunshine days in May:
11.5 days - Average sunshine days in June:
10.4 days
- Average sunshine days in July:
11.1 days - Average sunshine days in August:
13.6 days - Average sunshine days in September:
14.5 days - Average sunshine days in October:
15.3 days - Average sunshine days in November:
16.4 days - Average sunshine days in December:
15.7 days
The month with the most sunshine days is November (16.4 days).
The month with the least sunshine days is April (10.3 days).
Average UV index
Big Rock, 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 and December (UV index 1).
Average cloud cover
Big Rock, IL
The month with the most cloud cover is January (Cloud cover 61).
The months with the least cloud cover are August and September (Cloud cover 34).
Average visibility
Big Rock, IL
The months with the highest visibility are March, April, May, June, October, November and December (6mi).
The months with the lowest visibility are January, February, July, August and September (5mi).





