This report describes the typical weather at the Calgary/Springbank Airport (Calgary, Alberta, Canada) weather station over the course of an average December. It is based on the historical records from 1999 to 2012. Earlier records are either unavailable or unreliable.
Calgary, Alberta has a humid continental climate with warm summers and no dry season. The area within 25 mi of this station is covered by forests (70%), croplands (16%), grasslands (7%), and built-up areas (5%).
The month of December is characterized by essentially constant daily high temperatures, with daily highs around 29Â°F throughout the month, exceeding 46Â°F or dropping below 7Â°F only one day in ten.
Over the course of December, the length of the day is essentially constant. The shortest day of the month is December 22 with 7:53 hours of daylight; the longest day is December 1 with 8:14 hours of daylight.
The earliest sunrise is at 8:19am on December 1; the latest sunset is at 4:40pm on December 31; the latest sunrise is at 8:42am on December 31; the earliest sunset is at 4:30pm on December 10.
Daylight saving time is observed in 2012 but it neither starts nor ends in December, so the entire month is in standard time.
The median cloud cover is 72% (partly cloudy) and does not vary substantially over the course of the month.
On December 16, a representative day, the sky is clear or mostly clear 27% of the time, partly cloudy 6% of the time, and mostly cloudy or overcast 46% of the time.
The average probability that some form of precipitation will be observed in a given day is 29%, with little variation over the course of the month.
Throughout December, the most common forms of precipitation are light snow and moderate snow.
Light snow is the most severe precipitation observed during 82% of those days with precipitation. It is most likely around December 27, when it is observed during 25% of all days.
Moderate snow is the most severe precipitation observed during 11% of those days with precipitation. It is most likely around December 10, when it is observed during 3% of all days.
The likelihood of snow falling is highest around December 27, occurring in 29% of days.
Either snow rarely accumulates at this location in December or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 50% (comfortable) to 82% (humid) over the course of a typical December, rarely dropping below 33% (comfortable) and reaching as high as 97% (very humid).
The air is driest around December 31, at which time the relative humidity drops below 59% (mildly humid) three days out of four; it is most humid around December 6, rising above 72% (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 December, the dew point typically varies from 1Â°F (dry) to 17Â°F (dry) and is rarely below -14Â°F (dry) or above 28Â°F (dry).
Over the course of December typical wind speeds vary from 1 mph to 16 mph (calm to moderate breeze), rarely exceeding 27 mph (strong breeze).
The highest average wind speed of 8 mph (gentle breeze) occurs around December 31, 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 December 21, at which time the average daily maximum wind speed is 15 mph (moderate breeze).