This report describes the typical weather at the Spirit of St. Louis Airport (St. Louis, Missouri, United States) weather station over the course of an average February. It is based on the historical records from 1987 to 2012. Earlier records are either unavailable or unreliable.
St. Louis, Missouri has a humid continental climate with hot summers and no dry season. The area within 25 mi of this station is covered by forests (46%), croplands (19%), grasslands (18%), built-up areas (14%), and lakes and rivers (4%).
The month of February is characterized by rising daily high temperatures, with daily highs ranging from 42°F to 51°F over the course of the month, exceeding 67°F or dropping below 26°F only one day in ten.
Over the course of February, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 1:05 hours, implying an average day-over-day increase of 2.2 minutes.
The shortest day of the month is February 1 with 10:15 hours of daylight; the longest day is February 29 with 11:20 hours of daylight.
The earliest sunrise is at 6:35am on February 29; the latest sunset is at 5:55pm on February 29; the latest sunrise is at 7:09am on February 1; the earliest sunset is at 5:24pm on February 1.
Daylight savings time is observed in 2012 but it neither starts nor ends in February, so the entire month is in standard time.
The median cloud cover ranges from 70% (partly cloudy) to 77% (partly cloudy). The trend is for the sky to be clearing with the median cloud cover decreasing by 6% from the start to the end of the month.
On February 15, a representative day, the sky is clear or mostly clear 41% of the time, partly cloudy 7% of the time, and mostly cloudy or overcast 52% of the time.
The average probability that some form of precipitation will be observed in a given day is 46%, with little variation over the course of the month.
Throughout February, the most common forms of precipitation are light snow, light rain, and moderate rain.
Light snow is the most severe precipitation observed during 33% of those days with precipitation. It is most likely around February 2, when it is observed during 17% of all days.
Light rain is the most severe precipitation observed during 23% of those days with precipitation. It is most likely around February 29, when it is observed during 12% of all days.
Moderate rain is the most severe precipitation observed during 14% of those days with precipitation. It is most likely around February 29, when it is observed during 7% of all days.
The likelihood of snow falling is highest around February 1, occurring in 25% of days.
Either snow rarely accumulates at this location in February or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 45% (comfortable) to 88% (very humid) over the course of a typical February, rarely dropping below 26% (dry) and reaching as high as 100% (very humid).
The air is driest around February 29, at which time the relative humidity drops below 56% (mildly humid) three days out of four; it is most humid around February 1, rising above 82% (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 February, the dew point typically varies from 17°F (dry) to 35°F (dry) and is rarely below 1°F (dry) or above 51°F (very comfortable).
Over the course of February typical wind speeds vary from 0 mph to 16 mph (calm to moderate breeze), rarely exceeding 22 mph (fresh breeze).
The highest average wind speed of 9 mph (gentle breeze) occurs around February 29, at which time the average daily maximum wind speed is 16 mph (moderate breeze).
The lowest average wind speed of 8 mph (gentle breeze) occurs around February 3, at which time the average daily maximum wind speed is 14 mph (moderate breeze).