Climate and monthly weather forecastRomeoville, IL
Climate and monthly weather forecast
Weather in January
January, the same as December, in Romeoville, Illinois, is a freezing cold winter month, with an average temperature varying between 17.1°F (-8.3°C) and 28.8°F (-1.8°C). With average temperatures fluctuating between a high of 28.8°F (-1.8°C) and a low of 17.1°F (-8.3°C), January stands out as the coldest month. Weather in January »Weather in February
February, the last month of the winter in Romeoville, is an icy month, with an average temperature varying between 19.9°F (-6.7°C) and 32.5°F (0.3°C). February commences with an average high-temperature of a cold 32.5°F (0.3°C), showing little deviation from January's 28.8°F (-1.8°C). Weather in February »Weather in March
March, the first month of the spring in Romeoville, is a chilly month, with temperature in the range of an average high of 45.7°F (7.6°C) and an average low of 32°F (0°C). The transition to March introduces an increase in the average high-temperature, shifting from a cold 32.5°F (0.3°C) in February to a chilly 45.7°F (7.6°C). Weather in March »Weather in April
April is a refreshing spring month in Romeoville, Illinois, with temperature in the range of an average high of 57°F (13.9°C) and an average low of 41°F (5°C). The arrival of April brings a change in Romeoville's weather, with average high-temperatures moving from March's chilly 45.7°F (7.6°C) to a mild 57°F (13.9°C). Weather in April »Weather in May
The last month of the spring, May, is an agreeable month in Romeoville, Illinois, with an average temperature varying between 52.3°F (11.3°C) and 69.4°F (20.8°C). With the onset of May, Romeoville experiences a temperature shift, with the average high-temperature moving from a refreshing 57°F (13.9°C) in April to an agreeable 69.4°F (20.8°C). Weather in May »Weather in June
The first month of the summer, June, is a warm month in Romeoville, Illinois, with an average temperature ranging between max 78.6°F (25.9°C) and min 61.3°F (16.3°C). In Romeoville, stepping into June brings a temperature increase, moving up from May's pleasant 69.4°F (20.8°C) to a moderately hot 78.6°F (25.9°C). Weather in June »Weather in July
July, like June, in Romeoville, Illinois, is another warm summer month, with an average temperature varying between 81.9°F (27.7°C) and 65.7°F (18.7°C). July is the month that records the highest temperatures, with averages ranging from a high of 81.9°F (27.7°C) to a low of 65.7°F (18.7°C). July's heat index is computed to be a hot 87.8°F (31°C). Weather in July »Weather in August
The last month of the summer, August, is also a moderately hot month in Romeoville, Illinois, with temperature in the range of an average high of 80.2°F (26.8°C) and an average low of 63.9°F (17.7°C). The advent of August brings an average high-temperature of a still warm 80.2°F (26.8°C), exhibiting minor difference from the previous month. Weather in August »Weather in September
September, the first month of the autumn in Romeoville, is still a warm month, with temperature in the range of an average low of 57.4°F (14.1°C) and an average high of 74.3°F (23.5°C). A subtle change in temperatures is noted as August gives way to September, with average highs reducing from 80.2°F (26.8°C) to a still moderately hot 74.3°F (23.5°C). Weather in September »Weather in October
October, like September, is a moderate autumn month in Romeoville, Illinois, with an average temperature varying between 45.5°F (7.5°C) and 60.6°F (15.9°C). With the onset of October, Romeoville experiences a modest temperature adjustment, with the average high-temperature receding from a warm 74.3°F (23.5°C) in September to a mild 60.6°F (15.9°C). Weather in October »Weather in November
November, the last month of the autumn in Romeoville, is also a frosty month, with an average temperature ranging between min 33.4°F (0.8°C) and max 46.6°F (8.1°C). Arrival of November comes with a reduction in the average high-temperature, falling from a refreshing 60.6°F (15.9°C) in October to a frosty 46.6°F (8.1°C). Weather in November »Weather in December
December, the first month of the winter in Romeoville, is still a cold month, with temperature in the range of an average low of 24.6°F (-4.1°C) and an average high of 34.7°F (1.5°C). December's onset brings a slight change in high-temperatures, falling from a frosty 46.6°F (8.1°C) in November to a cold 34.7°F (1.5°C). Weather in December »Updated: Aug 15, 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
Romeoville's coldest month, January, registers temperatures that range from a high of 28.8°F (-1.8°C) to a low of 17.1°F (-8.3°C).
January and February, with an average relative humidity of 83%, are most humid months.
In Romeoville, during the entire year, the rain falls for 145.4 days and collects up to 22.83" (580mm) of precipitation.
January through May, October through December are months with snowfall in Romeoville.
January is the month with the most snowfall in Romeoville. Snow falls for 12.1 days and accumulates 3.11" (79mm) of snow.
Throughout the year, in Romeoville, there are 44.4 snowfall days, and 11.93" (303mm) of snow is accumulated.
January has the least sunshine of the year, with an average of 3.8h of sunshine.
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 is the month with the most rainfall. Rain falls for 16.4 days and accumulates 2.83" (72mm) of precipitation.
In Romeoville, snow does not fall in June through September.
June has the longest days of the year, with an average of 15h and 6min of daylight.
June through August, with an average maximum UV index of 6, are months with the highest UV index in Romeoville.
The highest temperatures are recorded in July, with averages reaching a high of 81.9°F (27.7°C) and a low of 65.7°F (18.7°C).
The months with the most sunshine are July and August, with an average of 9.9h of sunshine.
With an average relative humidity of 73%, October is the least humid month in Romeoville.
December is the month with the least rainfall. Rain falls for 7.1 days and accumulates 1.06" (27mm) of precipitation.
December has the shortest days of the year, with an average of 9h and 12min of daylight.
The month with the lowest UV index is December, with an average maximum UV index of 1.
Average temperature
Romeoville, IL
The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (28.8°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 (17.1°F).
Average pressure
Romeoville, 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:
30.1"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
Romeoville, IL
- Average wind speed in January:
9.7mph - Average wind speed in February:
9.6mph - Average wind speed in March:
9.3mph - Average wind speed in April:
9.5mph - Average wind speed in May:
8.1mph - Average wind speed in June:
7.1mph
The windiest month (with the highest average wind speed) is January (9.7mph).
The calmest month (with the lowest average wind speed) is August (6mph).
Average humidity
Romeoville, IL
The months with the highest relative humidity are January and February (83%).
The month with the lowest relative humidity is October (73%).
Average rainfall
Romeoville, IL
- Average rainfall in January:
1.22" - Average rainfall in February:
1.18" - Average rainfall in March:
1.3" - Average rainfall in April:
2.4" - Average rainfall in May:
2.83" - Average rainfall in June:
2.72"
- Average rainfall in July:
2.72" - Average rainfall in August:
2.48" - Average rainfall in September:
1.77" - Average rainfall in October:
2.01" - Average rainfall in November:
1.14" - Average rainfall in December:
1.06"
The wettest month (with the highest rainfall) is May (2.83").
The driest month (with the least rainfall) is December (1.06").
Average rainfall days
Romeoville, IL
- Average rainfall days in January:
5.7 days - Average rainfall days in February:
4.9 days - Average rainfall days in March:
11.8 days - Average rainfall days in April:
15 days - Average rainfall days in May:
16.4 days - Average rainfall days in June:
16.1 days
- Average rainfall days in July:
18.1 days - Average rainfall days in August:
16.3 days - Average rainfall days in September:
13.5 days - Average rainfall days in October:
11.9 days - Average rainfall days in November:
8.6 days - Average rainfall days in December:
7.1 days
The month with the highest number of rainy days is July (18.1 days).
The month with the least rainy days is February (4.9 days).
Average snowfall
Romeoville, IL
The month with the highest snowfall is January (3.11").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days
Romeoville, IL
- Average snowfall days in January:
12.1 days - Average snowfall days in February:
10.6 days - Average snowfall days in March:
6.2 days - Average snowfall days in April:
2.2 days - Average snowfall days in May:
0.1 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:
3.1 days - Average snowfall days in December:
9.7 days
The month with the highest number of snowfall days is January (12.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight / Average sunshine
Romeoville, 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 6min
- Average daylight in July:
14h and 48min - 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 54min - Average daylight in December:
9h and 12min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in January:
3h and 48min - Average sunshine in February:
3h and 54min - Average sunshine in March:
6h and 6min - Average sunshine in April:
7h and 36min - Average sunshine in May:
8h and 42min - Average sunshine in June:
9h and 42min
- Average sunshine in July:
9h and 54min - Average sunshine in August:
9h and 54min - Average sunshine in September:
8h and 42min - Average sunshine in October:
5h and 42min - Average sunshine in November:
5h and 6min - Average sunshine in December:
4h and 6min
The months with the most sunshine are July and August (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).
Average sunshine days
Romeoville, IL
- Average sunshine days in January:
14.8 days - Average sunshine days in February:
13.1 days - Average sunshine days in March:
14.1 days - Average sunshine days in April:
11.1 days - Average sunshine days in May:
11.7 days - Average sunshine days in June:
10.8 days
- Average sunshine days in July:
9.3 days - Average sunshine days in August:
10.8 days - Average sunshine days in September:
14.4 days - Average sunshine days in October:
16.3 days - Average sunshine days in November:
18.4 days - Average sunshine days in December:
16.2 days
The month with the most sunshine days is November (18.4 days).
The month with the least sunshine days is July (9.3 days).
Average UV index
Romeoville, IL
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover
Romeoville, IL
The month with the most cloud cover is January (Cloud cover 60).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility
Romeoville, IL
The months with the highest visibility are March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January and February (5mi).
