January weather forecast
Castleton, IL

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Weather in January

January, like December, is another subzero cold winter month in Castleton, Illinois, with an average temperature fluctuating between 17.8°F (-7.9°C) and 29.7°F (-1.3°C).

Temperature

Castleton, Illinois, records the coldest temperatures in January, averaging a high of 29.7°F (-1.3°C) and a low of 17.8°F (-7.9°C).

Humidity

In Castleton, the average relative humidity in January is 82%.

Rainfall

The month with the least rainfall is January, when the rain falls for 4.2 days and typically collects 0.59" (15mm) of precipitation.

Snowfall

Months with snowfall in Castleton, Illinois, are January through April, October through December. The month with the most snowfall is January, when snow falls for 8.6 days and typically aggregates up to 1.81" (46mm) of snow.

Daylight

The average length of the day in January in Castleton is 9h and 37min.
On the first day of January in Castleton, sunrise is at 7:23 am and sunset at 4:40 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 5:13 pm CST.

Sunshine

With an average of 3.9h of sunshine, January has the least sunshine of the year.

UV index

The months with the lowest UV index are January and December, with an average maximum UV index of 1. A UV Index value of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV rays for the average person.
Note: The maximum UV index of 1 during January translates into these guidelines:
While most people can stay under the sun for an hour without burning, children must always be guarded against sun exposure. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. Employ a wide-brim hat for potent defense against up to 50% of UV rays. Warning! The reflection from snow can nearly magnify the Sun's UV radiation twofold.
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Frequently asked questions

What month is the coldest in Castleton?

Castleton's coldest month, January, registers temperatures that range from a high of 29.7°F (-1.3°C) to a low of 17.8°F (-7.9°C).

How cold is January in Castleton?

In January, in Castleton, the average high-temperature is 29.7°F (-1.3°C), and the average low-temperature is 17.8°F (-7.9°C).

What is the average humidity in January in Castleton?

The average relative humidity in January in Castleton, Illinois, is 82%.

What is the driest month in Castleton?

January is the month with the least rainfall in Castleton, Illinois. Rain falls for 4.2 days and accumulates 0.59" (15mm) of precipitation.

How many days does it rain in January in Castleton?

In January, in Castleton, the rain falls for 4.2 days. Throughout January, 0.59" (15mm) of precipitation is accumulated.

What is the snowiest month in Castleton?

The month with the most snowfall is January, when snow falls for 8.6 days and typically aggregates up to 1.81" (46mm) of snow.

How much does it snow in Castleton in January?

In January, it is snowing for 8.6 days. Throughout January, 1.81" (46mm) of snow is accumulated.

How many hours of daylight does Castleton have in January?

In January, the average day length in Castleton, Illinois, is 9h and 37min.

When is the sunrise / sunset in January in Castleton?

In January, on the first day of the month, sunrise is at 7:23 am and sunset at 4:40 pm. On the last day of the month, in Castleton, sunrise is at 7:10 am and sunset at 5:13 pm CST.

What is the month with the least sunshine in Castleton?

January has the least sunshine of the year, with an average of 3.9h of sunshine.

How many hours of sunshine does Castleton have in January?

In January, the average sunshine duration is 3.9h.

What is the month with the lowest UV index in Castleton?

January and December, with an average maximum UV index of 1, are months with the lowest UV index in Castleton, Illinois.

How high is the UV index in January in Castleton?

In January, the average daily maximum UV index is 1. A UV Index estimate of 2, and below, represents a low health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in January
Castleton, IL

Average temperature in January - Castleton, IL
  • Average high temperature in January: 29.7°F

The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (29.7°F).

  • Average low temperature in January: 17.8°F

The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (17.8°F).

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Average pressure in January
Castleton, IL

Average pressure in January - Castleton, IL
  • Average pressure in January: 30.14"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in January
Castleton, IL

Average wind speed in January - Castleton, IL
  • Average wind speed in January: 10.5mph

The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest month (with the lowest average wind speed) is August (6.6mph).

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Average humidity in January
Castleton, IL

Average humidity in January - Castleton, IL
  • Average humidity in January: 82%

The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (72%).

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Average rainfall in January
Castleton, IL

Average rainfall in January - Castleton, IL
  • Average rainfall in January: 0.59"

The wettest month (with the highest rainfall) is May (2.24").
The driest month (with the least rainfall) is January (0.59").

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Average rainfall days in January
Castleton, IL

Average rainfall days in January - Castleton, IL
  • Average rainfall days in January: 4.2 days

The month with the highest number of rainy days is May (15.2 days).
The months with the least rainy days are January and February (4.2 days).

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Average snowfall in January
Castleton, IL

Average snowfall in January - Castleton, IL
  • Average snowfall in January: 1.81"

The month with the highest snowfall is January (1.81").
The months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days in January
Castleton, IL

Average snowfall days in January - Castleton, IL
  • Average snowfall days in January: 8.6 days

The month with the highest number of snowfall days is January (8.6 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
Castleton, IL

Average daylight in January / Average sunshine in January - Castleton, 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 18min).

  • Average sunshine in January: 3h and 5min

The months with the most sunshine are June and July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).

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Average sunshine days in January
Castleton, IL

Average sunshine days in January - Castleton, IL
  • Average sunshine days in January: 19.8 days

The month with the most sunshine days is November (21.3 days).
The month with the least sunshine days is May (12.8 days).

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Average UV index in January
Castleton, IL

Average UV index in January - Castleton, IL
  • Average UV index in January: 1

The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).

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Average cloud cover in January
Castleton, IL

Average cloud cover in January - Castleton, IL
  • Average cloud cover in January: 58

The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is September (Cloud cover 30).

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Average visibility in January
Castleton, IL

Average visibility in January - Castleton, 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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Castleton, Illinois, USA

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