This report describes the historical weather record at the Calgary International Airport (Calgary, Alberta, Canada) during 2012. This station has records back to July 1955.
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 (54%), croplands (35%), grasslands (6%), and built-up areas (5%)
Daylight saving time (DST) was observed at Calgary, Alberta during 2012. There were two time changes during 2012:
2012 was a leap year and thus has 366 days rather than the normal 365. Leap years occur every fourth year and the extra day is always February 29th. In 2012 February 29th falls on a Wednesday.
The summer and winter solstices and the spring and fall equinoxes mark the passing of the seasons. They fall on nearly the same day each year, with differences of a day or two depending on the year. In 2012 they occurred on:
|Spring Equinox||Tuesday, 20 March 2012.|
|Summer Solstice||Wednesday, 20 June 2012.|
|Fall Equinox||Saturday, 22 September 2012.|
|Winter Solstice||Friday, 21 December 2012.|
The hottest day of 2012 was July 9, with a high temperature of 86°F. For reference, on that day the average high temperature is 71°F and the high temperature exceeds 81°F only one day in ten. The hottest month of 2012 was August with an average daily high temperature of 76°F.
Relative to the average, the hottest day was January 4. The high temperature that day was 59°F, compared to the average of 27°F, a difference of 32°F. In relative terms the warmest month was September, with an average high temperature of 71°F, compared to an typical value of 63°F.
The longest warm spell was from September 17 to October 2, constituting 16 consecutive days with warmer than average high temperatures. The month of September had the largest fraction of warmer than average days with 80% days with higher than average high temperatures.
The coldest day of 2012 was January 18, with a low temperature of -26°F. For reference, on that day the average low temperature is 9°F and the low temperature drops below -12°F only one day in ten. The coldest month of 2012 was December with an average daily low temperature of 5°F.
Relative to the average, the coldest day was January 18. The low temperature that day was -26°F, compared to the average of 9°F, a difference of 35°F. In relative terms the coldest month was December, with an average low temperature of 5°F, compared to an typical value of 11°F.
The longest cold spell was from October 20 to November 1, constituting 13 consecutive days with cooler than average low temperatures. The month of December had the largest fraction of cooler than average days with 68% days with lower than average low temperatures.
The longest freezing spell was from December 17 to December 28, constituting 12 consecutive days with temperatures strictly below freezing.
The clearest month of 2012 was September, with 37% of days being more clear than cloudy.
The cloudiest month of 2012 was October, with 84% of days being more cloudy than clear. The longest spell of cloudy weather was from October 19 to November 4, constituting 17 consecutive days that were cloudier than they were clear.
This station provides hourly reports of significant weather events at and around the station, but does not report the quantity of precipitation at the station itself. This is common for weather stations located outside of the United States, and for a small subset of stations in the United States that are located at lesser used and smaller airports.
This station reports when significant weather events (including precipitation) are visually observed at or near the station. Such events do not always correspond to measured quantities of liquid equivalent precipitation, such as when the event is near by not at the station, or in the case of solid precipitation that does not melt in the collection basin.
The day in 2012 with the most precipitation observations was November 8. There were 24 hourly weather reports that day (out of a maximum of 24) in which some form of precipitation was observated at or near the station. The month with the most precipitation observations was October, with 194 hourly present weather reports involving some form of precipitation.
As determined by the present weather reports, the longest dry spell was from September 10 to September 25, constituting 16 consecutive days with no observed precipitation. The month with the largest fraction of days without observed precipitation was January, with 74% of days reporting no observed precipitation at all.
The month with the largest fraction of days with at least some observed precipitation was June, with 73% of days reporting some observed precipitation.
In this section we consider only those weather reports that indicate liquid precipitation. For the purposes of this analysis, we include thunderstorms even though some thunderstorms are not accompanied by liquid precipitation.
The month of 2012 with the largest number of those reports was June, with a total of 120 reports. The day with the largest number of those reports was May 1, with a total of 21 reports.
This station reports when snow is observed falling but does not report the quantity of snow that has fallen or the depth of snow on the ground.
In this section we consider hourly weather reports that contain an observation of falling snow. These reports do not necessarily correspond to accumulation.
The first reported snow fall in 2012 was on August 1; the last was on May 25. The month of 2012 with the largest number of those reports was December, with a total of 170 reports. The day with the largest number of those reports was November 8, with a total of 24 reports.
Humidity is an important factor in determining how weather conditions feel to a person experiencing them. Hot and humid days feel even hotter than hot and dry days because the high level of water content in humid air discourages the evaporation of sweat from a person's skin.
When reading the graph below, keep in mind that the hottest part of the day tends to be the least humid, so the daily low (brown) traces are more relevant for understanding daytime comfort than the daily high (blue) traces, which typically occur during the night. Applying that observation, the least humid month of 2012 was September with an average daily low humidity of 29%, and the most humid month was November with an average daily low humidity of 59%.
But it is important to keep in mind that humidity does not tell the whole picture and the dew point is often a better measure of how comfortable a person will find a given set of weather conditions. Please see the next section for continued discussion of this point.
Dew point is the temperature below which water vapor will condense into liquid water. It is therefore also related to the rate of evaporation of liquid water. Since the evaporation of sweat is an important cooling mechanism for the human body, the dew point is an important measurement for understanding how dry, comfortable, or humid a given set of weather conditions will feel.
Generally speaking, dew points below 50°F will feel a bit dry to some people, but comfortable to people accustomed to dry conditions; dew points from 50°F to 68°F are fairly comfortable to most people, and dew points above 68°F are increasingly uncomfortable, becoming oppressive around 77°F.
To take some examples, and basing our categorization on the daily high dew point in 2012, January had 31 dry days, no comfortable days, and no humid days; April had 30 dry days, no comfortable days, and no humid days; July had 1 dry day, 29 comfortable days, and 1 humid day; and October had 31 dry days, no comfortable days, and no humid days.
The highest sustained wind speed was 64 mph, occurring on June 8; the highest daily mean wind speed was 23 mph (June 10); and the highest wind gust speed was 60 mph (August 14).
The windiest month was October, with an average wind speed of 12 mph. The least windy month was February, with an average wind speed of 8 mph.
Visibility is the maximum distance at which a given reference object or light can be clearly discerned. In the United States, visibilities that are greater than or equal to 10 miles are typically reported as 10 miles.
The day of 2012 with the lowest average visibility was December 1, with an average visibility of 1.4 mi. The month with the lowest average visibility was October, with an average visibility of 17.0 mi. With an average visibility of 25.7 mi, the month of June had the highest average visibility.
The cloud ceiling is the altitude of the lowest layer of clouds that are at categorized as broken (mostly cloudy) or overcast (cloudy). If no such cloud layer exists then the ceiling is unlimited and no value is reported.
The day of 2012 with the lowest average cloud ceiling was October 29, with an average cloud ceiling of 412'. The month with the lowest average cloud ceiling was October, with an average cloud ceiling of 7431'. The month of September has the highest average cloud ceiling, with an average cloud ceiling of 16725'.