According to weather forecast, it's goin' to be snowing tonight and continues till Sat. The temperature is also drops down to almost -19 degrees of centigrade. Among 12 months of a year, there are 8 months winter, 1 month spring, 1 month fall (autumn) and 2 months summer in Calgary. City of Calgary (Calgary's municipality) asks all Calgarians to clean their sidewalks. It's mandatory. The main street sidewalks is usually cleaned by small special vehicles or sometimes employees who are on contract with the City.