Calgary has a continental climate with long winters, but highly variable and short, warm summers. The climate is greatly influenced by the elevation of the city and the proximity of the Rocky Mountains. Although the cold Calgary winters can be very uncomfortable, hot, dry winds called Chinooks, occasionally blow steadily over the city from the Pacific Ocean during the winter months, giving Calgarians a break from the cold. These winds have sometimes raises the temperature above 15 ° C in a few hours and can last several days. The Chinooks are a regular feature of Calgary winters. More than half the winter days have a maximum temperature above 0 ° C. On occasion, the temperature in winter may approach 20 ° C.
Calgary is a city of extremes, and temperatures can vary between a record cold of -45 ° C in 1893 to a record maximum of 36 ° C in 1919. Calgary is experiencing temperatures of summer days over 30 ° C roughly four days a year. The temperature falls below -30 ° C five days per year on average, but periods of extreme cold do not last very long in general. According to Environment Canada, the average temperature in Calgary varies between an average of -9 ° C in January to an average of 16 ° C in July.
As a result of the high altitude of Calgary, a summer evening can be rather cold, the summer average minimum is 8 ° C and frost may occur in any month of the year. The city has already seen snow even in July and August. With an average relative humidity of 55% in winter and 45% in summer, Calgary has a semi-arid climate typical of other cities in the Great Plains of the West and the Canadian Prairies. Unlike other cities further east, like Toronto, Montreal, Winnipeg and even the humidity is almost never a factor during the summer in Calgary.
The city is one of the sunniest in Canada, with an average of 2 405 hours of sunshine annually. Calgary receives an average of 413 mm of precipitation, including 301 mm of rain and snow the rest. Most precipitation falls from May to August, the month of June experienced the highest average rainfall. In June 2005, Calgary received 248 mm of precipitation, making it the wettest month in the history of the city. Droughts are not unusual and can occur at any time of year.