This report describes the typical weather at the Greater Peoria Regional Airport (Peoria, Illinois, United States) weather station over the course of an average January. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
Peoria, Illinois has a humid continental climate with hot summers and no dry season. The area within 25 mi of this station is covered by croplands (82%), grasslands (7%), forests (6%), lakes and rivers (3%), and built-up areas (2%).
The month of January is characterized by essentially constant daily high temperatures, with daily highs around 32°F throughout the month, exceeding 48°F or dropping below 15°F only one day in ten.
Over the course of January, the length of the day is gradually increasing. The shortest day of the month is January 3 with 9:20 hours of daylight; the longest day is January 31 with 10:05 hours of daylight.
The earliest sunrise is at 7:10am on January 31; the latest sunset is at 5:15pm on January 31; the latest sunrise is at 7:23am on January 3; the earliest sunset is at 4:42pm on January 1.
Daylight savings time is observed in 2012 but it neither starts nor ends in January, so the entire month is in standard time.
The median cloud cover is 85% (mostly cloudy) and does not vary substantially over the course of the month.
On January 16, a representative day, the sky is clear or mostly clear 37% of the time, partly cloudy 8% of the time, and mostly cloudy or overcast 54% of the time.
The average probability that some form of precipitation will be observed in a given day is 51%, with little variation over the course of the month.
Throughout January, the most common forms of precipitation are light snow, moderate snow, moderate rain, and light rain.
Light snow is the most severe precipitation observed during 49% of those days with precipitation. It is most likely around January 17, when it is observed during 26% of all days.
Moderate snow is the most severe precipitation observed during 17% of those days with precipitation. It is most likely around January 11, when it is observed during 9% of all days.
Moderate rain is the most severe precipitation observed during 11% of those days with precipitation. It is most likely around January 1, when it is observed during 6% of all days.
Light rain is the most severe precipitation observed during 11% of those days with precipitation. It is most likely around January 3, when it is observed during 6% of all days.
The likelihood of snow falling is highest around January 16, occurring in 37% of days.
Accumulation at this location in January is about as likely as not. The chances of there being snow on the ground are highest around January 19, occurring 51% of the time.
The snow is typically at its deepest on January 17, with a median depth of 2.4"; the depth exceeds 5.9" only one year out of ten.
The relative humidity typically ranges from 60% (mildly humid) to 89% (very humid) over the course of a typical January, rarely dropping below 44% (comfortable) and reaching as high as 100% (very humid).
The air is driest around January 31, at which time the relative humidity drops below 69% (mildly humid) three days out of four; it is most humid around January 1, rising above 83% (humid) three days out of four.
Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.
Over the course of a typical January, the dew point typically varies from 10°F (dry) to 25°F (dry) and is rarely below -11°F (dry) or above 40°F (dry).
Over the course of January typical wind speeds vary from 4 mph to 16 mph (light breeze to moderate breeze), rarely exceeding 23 mph (fresh breeze).
The highest average wind speed of 10 mph (gentle breeze) occurs around January 19, at which time the average daily maximum wind speed is 16 mph (moderate breeze).
The lowest average wind speed of 10 mph (gentle breeze) occurs around January 30, at which time the average daily maximum wind speed is 15 mph (moderate breeze).