Montreal's climate varies between extremes. Summers are warm and humid with average daytime temperatures reaching 79 degrees Fahrenheit (26 degrees Celsius), whilst the winters are cold and snowy, averaging only 27 degrees Fahrenheit (-3 degrees Celsius) during the day. Gloves, hat and scarf are essential during the winter, whilst for the summer loose-fitting natural-fibre garments are perfect for daytime with the addition of a sweater or light jacket in the evening.

Growth was slow until the early 18th century. Montreal became a significant fur-trading post in about 1710, and other forms of commerce soon followed In the early years of the 19th century, Montreal made rapid economic progress. Steam navigation began on the St. Lawrence in 1809. The Lachine Canal, forerunner of the St. Lawrence Seaway, was started in 1821, and during the 1830s and 1840s railroads from Toronto, New York City, Boston, and other cities reached Montreal. In 1860 the prince of Wales dedicated the Victoria Bridge across the St. Lawrence. When the Canadian Confederation was proclaimed in 1867 Montreal was the largest metropolis in Canada.