January weather forecast
Rock Falls, IL

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Weather in January

January, like December, is another subzero cold winter month in Rock Falls, Illinois, with an average temperature varying between 27.7°F (-2.4°C) and 14.9°F (-9.5°C).

Temperature

Rock Falls's January weather reaches an average high of 27.7°F (-2.4°C) and an average low of 14.9°F (-9.5°C), making it the coldest month.

Humidity

The months with the highest humidity are January and July, with an average relative humidity of 85%.

Rainfall

The months with the least rainfall in Rock Falls are January and February Rain falls for 4.8 days and accumulates 0.75" (19mm) of rain.

Snowfall

Months with snowfall are January through April, October through December. January is the month with the most snowfall in Rock Falls. Snow falls for 10.2 days and accumulates 2.56" (65mm) of snow.

Daylight

In January, the average length of the day in Rock Falls is 9h and 34min.
On the first day of January, sunrise is at 7:25 am and sunset at 4:38 pm. On the last day of the month, sunrise is at 7:12 am and sunset at 5:12 pm CST.

Sunshine

With an average of 3.8h of sunshine, January has the least sunshine of the year in Rock Falls, Illinois.

UV index

The average daily maximum UV index in January in Rock Falls, Illinois, is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for the average person.
Note: The maximum UV index, 2 during January, leads to the following recommendations:
Prolonged sun exposure generally does not trouble most people. However, it is vital to ensure protection for babies, children, and individuals with sensitive skin. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Stay alert! Snow's reflective properties can almost double the UV radiation from the Sun.
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Frequently asked questions

What is the coldest time of year in Rock Falls?

The coldest temperatures occur during January, when averages reach a peak of 27.7°F (-2.4°C) and a low of 14.9°F (-9.5°C).

How cold is it in Rock Falls in January?

The high-temperature during January is 27.7°F (-2.4°C) and the low-temperature is 14.9°F (-9.5°C).

What is the most humid month in Rock Falls?

The months with the highest humidity in Rock Falls are January and July, with an average relative humidity of 85%.

What is the average humidity in January in Rock Falls?

In January, the average relative humidity in Rock Falls is 85%.

What is the driest month in Rock Falls?

The months with the least rainfall in Rock Falls, Illinois, are January and February Rain falls for 4.8 days and accumulates 0.75" (19mm) of rain.

How much does it rain in Rock Falls in January?

In Rock Falls, Illinois, in January, it is raining for 4.8 days, with typically 0.75" (19mm) of accumulated precipitation.

What is the snowiest month in Rock Falls?

January is the month with the most snowfall in Rock Falls, Illinois. Snow falls for 10.2 days and accumulates 2.56" (65mm) of snow.

How many days does it snow in January in Rock Falls?

In Rock Falls, Illinois, during January, snow falls for 10.2 days and regularly aggregates up to 2.56" (65mm) of snow.

What is the average length of the day in January in Rock Falls?

In Rock Falls, Illinois, the average day length in January is 9h and 34min.

When is the sunrise / sunset in January in Rock Falls?

On the first day of January, sunrise is at 7:25 am and sunset at 4:38 pm. On the last day of the month, sunrise is at 7:12 am and sunset at 5:12 pm CST.

What is the month with the least sunshine in Rock Falls?

January has the least sunshine of the year in Rock Falls, Illinois, with an average of 3.8h of sunshine.

How long on average sun shines in January in Rock Falls?

The average sunshine duration in January is 3.8h.

What is the UV index reading in January in Rock Falls?

In January, the average daily maximum UV index in Rock Falls is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability from exposure to Sun's UV rays.
Today
Tomorrow
Long-term
YearJanuaryFMAMJJASOND
Dec
January
Feb
Average high temperature
33.8°F 1°C
27.7°F -2.4°C
31.6°F -0.2°C
Average low temperature
23.2°F -4.9°C
14.9°F -9.5°C
18.5°F -7.5°C
Average pressure
30.1" 765mmHg
30.12" 765mmHg
30.11" 765mmHg
Average wind speed
9.5mph 15.3km/h
10mph 16.1km/h
10.1mph 16.3km/h
Average max. wind speed
10.1mph 16.3km/h
10.7mph 17.2km/h
10.8mph 17.4km/h
Average wind speed gusts
15.2mph 24.5km/h
16mph 25.7km/h
16.1mph 25.9km/h
Average humidity
82%
85%
84%
Average rainfall
0.83" 21mm
0.75" 19mm
0.75" 19mm
Average rainfall days
5.7
4.8
5
Average snowfall
1.3" 33mm
2.56" 65mm
2.09" 53mm
Average snowfall days
7.4
10.2
8.2
Average daylight
9h 1min
9h 4min
10h 4min
Average sunshine
4h 1min
3h 5min
4h 0min
Average sunshine days
18.8
17
16.2
Average UV index
1
2
2
Average cloud cover
57%
60%
57%
Average visibility
6mi 9.7km
6mi 9.7km
6mi 9.7km

Average temperature in January
Rock Falls, IL

Average temperature in January - Rock Falls, IL
  • Average high temperature in January: 27.7°F

The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (27.7°F).

  • Average low temperature in January: 14.9°F

The month with the highest average low temperature is July (63.9°F).
The coldest month (with the lowest average low temperature) is January (14.9°F).

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Average pressure in January
Rock Falls, IL

Average pressure in January - Rock Falls, IL
  • Average pressure in January: 30.12"Hg

The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in January
Rock Falls, IL

Average wind speed in January - Rock Falls, IL
  • Average wind speed in January: 10mph

The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.4mph).

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Average humidity in January
Rock Falls, IL

Average humidity in January - Rock Falls, IL
  • Average humidity in January: 85%

The months with the highest relative humidity are January and July (85%).
The month with the lowest relative humidity is October (73%).

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Average rainfall in January
Rock Falls, IL

Average rainfall in January - Rock Falls, IL
  • Average rainfall in January: 0.75"

The wettest month (with the highest rainfall) is May (2.83").
The driest months (with the least rainfall) are January and February (0.75").

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Average rainfall days in January
Rock Falls, IL

Average rainfall days in January - Rock Falls, IL
  • Average rainfall days in January: 4.8 days

The month with the highest number of rainy days is May (17.3 days).
The month with the least rainy days is January (4.8 days).

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Average snowfall in January
Rock Falls, IL

Average snowfall in January - Rock Falls, IL
  • Average snowfall in January: 2.56"

The month with the highest snowfall is January (2.56").
The months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days in January
Rock Falls, IL

Average snowfall days in January - Rock Falls, IL
  • Average snowfall days in January: 10.2 days

The month with the highest number of snowfall days is January (10.2 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

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Average daylight in January /
Average sunshine in January
Rock Falls, IL

Average daylight in January / Average sunshine in January - Rock Falls, IL
  • Average daylight in January: 9h and 4min

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 5min

The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).

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Average sunshine days in January
Rock Falls, IL

Average sunshine days in January - Rock Falls, IL
  • Average sunshine days in January: 17 days

The months with the most sunshine days are November and December (18.8 days).
The month with the least sunshine days is June (11.3 days).

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Average UV index in January
Rock Falls, IL

Average UV index in January - Rock Falls, IL
  • Average UV index in January: 2

The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is December (UV index 1).

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Average cloud cover in January
Rock Falls, IL

Average cloud cover in January - Rock Falls, 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 September (Cloud cover 31).

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Average visibility in January
Rock Falls, IL

Average visibility in January - Rock Falls, IL
  • Average visibility in January: 6mi

The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).

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Rock Falls, Illinois, USA

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