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
January is the coldest month, exhibiting average temperatures of 28.9°F (-1.7°C) at the peak and 19.4°F (-7°C) at the base.Humidity
January is the most humid month, with an average relative humidity of 82%.Rainfall
In River Forest, in January, during 6.5 rainfall days, 1.69" (43mm) of precipitation is typically accumulated. In River Forest, during the entire year, the rain falls for 157.8 days and collects up to 33.7" (856mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In River Forest, during January, snow falls for 10.8 days and regularly aggregates up to 4.21" (107mm) of snow. Throughout the year, in River Forest, there are 40.3 snowfall days, and 16.81" (427mm) of snow is accumulated.Daylight
In River Forest, the average length of the day in January is 9h and 33min.On the first day of the month, sunrise is at 7:18 am and sunset at 4:30 pm. On the last day of January, in River Forest, sunrise is at 7:04 am and sunset at 5:04 pm CST.
Sunshine
With an average of 3.7h of sunshine, January has the least sunshine of the year.UV index
January and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.Note: In January, the average maximum UV index of 1 translates into the following recommendations:
Long-term sun exposure is typically not a concern for most. However, those with sensitive skin, infants, and children must always have protection. To avoid the Sun's strongest rays, limit exposure around the mid-day period. A hat with a broad brim is indispensable, filtering out up to half of UV rays. Be cautious! The UV radiation from the Sun can be magnified almost twofold by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What time of the year is the coldest?
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?
How much does it snow in January?
How many hours of daylight does River Forest have in January?
When are sunrise and sunset in January?
What is the month with the least sunshine?
How many hours of sunshine does River Forest have in January?
When is the lowest UV index?
How high is the UV index in January?
Average temperature in January
River Forest, IL
- Average high temperature in January: 28.9°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is January (28.9°F).
- Average low temperature in January: 19.4°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 (19.4°F).
Average pressure in January
River Forest, 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
River Forest, IL
- Average wind speed in January: 11.1mph
The windiest month (with the highest average wind speed) is January (11.1mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).
Average humidity in January
River Forest, IL
- Average humidity in January: 82%
The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is October (72%).
Average rainfall in January
River Forest, IL
- Average rainfall in January: 1.69"
The wettest month (with the highest rainfall) is May (4.49").
The driest month (with the least rainfall) is December (1.57").
Average rainfall days in January
River Forest, IL
- Average rainfall days in January: 6.5 days
The month with the highest number of rainy days is May (18.8 days).
The month with the least rainy days is February (5.1 days).
Average snowfall in January
River Forest, IL
- Average snowfall in January: 4.21"
The month with the highest snowfall is February (4.69").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in January
River Forest, IL
- Average snowfall days in January: 10.8 days
The month with the highest number of snowfall days is January (10.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in January /
Average sunshine in January
River Forest, IL
- Average daylight in January: 9h and 3min
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 4min
The month with the most sunshine is August (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in January
River Forest, IL
- Average sunshine days in January: 14.3 days
The month with the most sunshine days is December (16.7 days).
The month with the least sunshine days is July (9.9 days).
Average UV index in January
River Forest, IL
- Average UV index in January: 1
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 in January
River Forest, IL
- Average cloud cover in January: 61
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in January
River Forest, IL
- Average visibility in January: 6mi
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).
River Forest, Illinois, USA
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