Contents
- Weather in January
- Frequently asked questions
- Average temperature in January
- Average pressure in January
- Average wind speed in January
- Average humidity in January
- Average rainfall in January
- Average rainfall days in January
- Average snowfall in January
- Average snowfall days in January
- Average daylight in January
- Average sunshine in January
- Average sunshine days in January
- Average UV index in January
- Average cloud cover in January
- Average visibility in January
Weather in January
Temperature
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.Humidity
The months with the highest humidity are January and February, with an average relative humidity of 83%.Rainfall
In Romeoville, during January, the rain falls for 5.7 days and regularly aggregates up to 1.22" (31mm) of precipitation. In Romeoville, during the entire year, the rain falls for 145.4 days and collects up to 22.83" (580mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. The month with the most snowfall is January, when snow falls for 12.1 days and typically aggregates up to 3.11" (79mm) of snow.Daylight
The average length of the day in January is 9h and 34min.On the first day of the month, sunrise is at 7:19 am and sunset at 4:32 pm. On the last day of January, sunrise is at 7:05 am and sunset at 5:06 pm CST.
Sunshine
The month with the least sunshine is January, with an average of 3.8h of sunshine.UV index
In Romeoville, the average daily maximum UV index in January is 2. A UV Index of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV radiation for ordinary individuals.Note: In January, the maximum UV index of 2 suggests this advice:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Beware! Reflection from snow can magnify the Sun's UV radiation nearly twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the coldest months?
How cold is it in January?
What is the most humid month?
What is the average humidity in January?
How much does it rain in January?
What is the snowiest month?
How much does it snow in January?
How many hours of daylight does Romeoville have in January?
When is the sunrise / sunset in January?
What is the month with the least sunshine?
How many hours of sunshine does Romeoville have in January?
How high is the UV index in January?
Average temperature in January
Romeoville, IL
- Average high temperature in January: 28.8°F
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).
- Average low temperature in January: 17.1°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 in January
Romeoville, IL
- Average pressure in January: 30.11"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 in January
Romeoville, IL
- Average wind speed in January: 9.7mph
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 in January
Romeoville, IL
- Average humidity in January: 83%
The months with the highest relative humidity are January and February (83%).
The month with the lowest relative humidity is October (73%).
Average rainfall in January
Romeoville, IL
- Average rainfall in January: 1.22"
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 in January
Romeoville, IL
- Average rainfall days in January: 5.7 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 in January
Romeoville, IL
- Average snowfall in January: 3.11"
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 in January
Romeoville, IL
- Average snowfall days in January: 12.1 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 in January /
Average sunshine in January
Romeoville, IL
- Average daylight in January: 9h and 4min
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 5min
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 in January
Romeoville, IL
- Average sunshine days in January: 14.8 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 in January
Romeoville, IL
- Average UV index in January: 2
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 in January
Romeoville, IL
- Average cloud cover in January: 60
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 in January
Romeoville, IL
- Average visibility in January: 5mi
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).
Romeoville, Illinois, USA
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