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, on average, is the coldest month in Decatur, registering a high temperature of 32.9°F (0.5°C) and a low of 21.2°F (-6°C).Humidity
In January, the average relative humidity in Decatur is 79%.Rainfall
In Decatur, during January, the rain falls for 6.3 days and regularly aggregates up to 1.06" (27mm) of precipitation. In Decatur, during the entire year, the rain falls for 130.2 days and collects up to 16.34" (415mm) of precipitation.Snowfall
January through April, November and December are months with snowfall. The month with the most snowfall is January, when snow falls for 7.2 days and typically aggregates up to 1.85" (47mm) of snow.Daylight
The average length of the day in January is 9h and 44min.On the first day of the month, sunrise is at 7:17 am and sunset at 4:41 pm. On the last day of January, in Decatur, sunrise is at 7:04 am and sunset at 5:13 pm CST.
Sunshine
January has the least sunshine of the year in Decatur, Illinois, with an average of 4.1h 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 reading of 2, and below, represents a minimal health hazard from unsafe exposure to UV radiation for average individuals.Note: During January, 2 as the daily maximum UV index converts into the following advice:
Extended sunlight exposure does not pose significant problems for most people, except for children, infants, and people with fair skin who always need shielding. Protect yourself from the midday Sun's peak UV radiation by minimizing exposure. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Be aware! The intensity of the Sun's UV radiation can be amplified nearly twice due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest month in Decatur?
How cold is January in Decatur?
What is the average humidity in January in Decatur?
How many days does it rain in January in Decatur?
When does it snow the most in Decatur?
How much does it snow in Decatur in January?
How many hours of daylight does Decatur have in January?
When is the sunrise / sunset in January in Decatur?
What is the month with the least sunshine in Decatur?
How many hours of sunshine does Decatur have in January?
What is the month with the lowest UV index in Decatur?
What is the UV index reading in January in Decatur?
Average temperature in January
Decatur, IL
- Average high temperature in January: 32.9°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (32.9°F).
- Average low temperature in January: 21.2°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 (21.2°F).
Average pressure in January
Decatur, IL
- Average pressure in January: 30.15"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in January
Decatur, IL
- Average wind speed in January: 10.7mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).
Average humidity in January
Decatur, IL
- Average humidity in January: 79%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (70%).
Average rainfall in January
Decatur, IL
- Average rainfall in January: 1.06"
The wettest month (with the highest rainfall) is May (2.01").
The driest months (with the least rainfall) are February and December (0.87").
Average rainfall days in January
Decatur, IL
- Average rainfall days in January: 6.3 days
The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is February (5.8 days).
Average snowfall in January
Decatur, IL
- Average snowfall in January: 1.85"
The month with the highest snowfall is January (1.85").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in January
Decatur, IL
- Average snowfall days in January: 7.2 days
The month with the highest number of snowfall days is January (7.2 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
Decatur, IL
- Average daylight in January: 9h and 4min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in January: 4h and 1min
The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in January
Decatur, IL
- Average sunshine days in January: 19.5 days
The month with the most sunshine days is October (19.8 days).
The month with the least sunshine days is May (11.5 days).
Average UV index in January
Decatur, IL
- Average UV index in January: 2
The months with the highest UV index are 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
Decatur, IL
- Average cloud cover in January: 56
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is September (Cloud cover 29).
Average visibility in January
Decatur, 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).
Decatur, Illinois, USA
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