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
O'Fallon's temperature records reveal January as the coldest month, marked by average highs of 37.8°F (3.2°C) and lows of 24.6°F (-4.1°C).Humidity
The average relative humidity in January is 76%.Rainfall
In O'Fallon, Illinois, during January, the rain falls for 4.8 days and regularly aggregates up to 0.71" (18mm) of precipitation. In O'Fallon, during the entire year, the rain falls for 108.8 days and collects up to 10.24" (260mm) of precipitation.Snowfall
Months with snowfall are January through March, November and December. The month with the most snowfall is January, when snow falls for 4.7 days and typically aggregates up to 0.51" (13mm) of snow.Daylight
The average length of the day in January is 9h and 50min.On the first day of the month, sunrise is at 7:17 am and sunset at 4:48 pm. On the last day of January, sunrise is at 7:06 am and sunset at 5:19 pm CST.
Sunshine
January has the least sunshine of the year in O'Fallon, with an average of 4.5h of sunshine.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV rays for ordinary individuals.Note: In January, a daily maximum UV index of 2 leads to the following instructions:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. A hat with a broad brim is indispensable, filtering out up to half of UV rays. Take careful note! The UV radiation of the Sun can be nearly doubled by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest month?
Is it cold in O'Fallon during January?
What is the average humidity in January?
How many days does it rain in January?
What is the snowiest month?
How many days does it snow in January?
How many hours of daylight does O'Fallon have in January?
What time are sunrise and sunset in January?
What is the month with the least sunshine in O'Fallon?
How long on average sun shines in January?
What is the month with the lowest UV index?
How high is the UV index in January?
Average temperature in January
O'Fallon, IL
- Average high temperature in January: 37.8°F
The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (37.8°F).
- Average low temperature in January: 24.6°F
The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (24.6°F).
Average pressure in January
O'Fallon, IL
- Average pressure in January: 30.16"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in January
O'Fallon, IL
- Average wind speed in January: 9.5mph
The windiest month (with the highest average wind speed) is January (9.5mph).
The calmest month (with the lowest average wind speed) is July (5.6mph).
Average humidity in January
O'Fallon, IL
- Average humidity in January: 76%
The months with the highest relative humidity are May, July and August (79%).
The month with the lowest relative humidity is October (70%).
Average rainfall in January
O'Fallon, IL
- Average rainfall in January: 0.71"
The wettest month (with the highest rainfall) is July (1.42").
The driest month (with the least rainfall) is December (0.31").
Average rainfall days in January
O'Fallon, IL
- Average rainfall days in January: 4.8 days
The month with the highest number of rainy days is July (13.1 days).
The month with the least rainy days is December (4.6 days).
Average snowfall in January
O'Fallon, IL
- Average snowfall in January: 0.51"
The month with the highest snowfall is January (0.51").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in January
O'Fallon, IL
- Average snowfall days in January: 4.7 days
The month with the highest number of snowfall days is January (4.7 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in January /
Average sunshine in January
O'Fallon, IL
- Average daylight in January: 9h and 5min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in January: 4h and 3min
The months with the most sunshine are June and July (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).
Average sunshine days in January
O'Fallon, IL
- Average sunshine days in January: 23.1 days
The month with the most sunshine days is December (23.6 days).
The months with the least sunshine days are May and July (15.5 days).
Average UV index in January
O'Fallon, IL
- Average UV index in January: 2
The months with the highest UV index are May, 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 in January
O'Fallon, IL
- Average cloud cover in January: 51
The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in January
O'Fallon, 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).
O'Fallon, Illinois, USA
Weather forecast for your location
2. Allow the app to use your location