Historical records reveal how Canada’s weather has changed over the centuries

People stand near floodwaters along St. James Street in Montréal in April 1886. Flooding inundated large parts of the city’s West Island and affected some 20,000 families. (CP PHOTO/National Archives of Canada) Historical records reveal how Canada’s weather has changed over the centuries Published: July 5, 2026 9.46am EDT Share article Print article Tornadoes, floods, wildfires and storms have all been in the news recently, and all are taken as harbingers of a coming climate catastrophe. The word “unprecedented” is often used in such reports, but are these disruptive weather events unusual for the various climates of Canada? How can we tell? It feels as if we are adrift in a sea of events, statistics and crises, with no anchors or waypoints. As with many disciplines, we climatologists turn to history to stabilize ourselves in a constantly churning sea of change. Flood markers and rain gauges date back millennia, while modern thermometers and barometers were invented near the middle of the 17th century. People have been recording weather and climate ever since, leaving us with several centuries of historical weather diaries and climatic records. In Canada, the earliest instrumental records date to the first half of the 18th century, with recordings from Hudson Bay in the 1730s and Québec City in the 1740s. We have records stretching back centuries. With these records, we can gain insights on an incredible scale, over both time and space. When we can access the original documents, we can look at weather recordings taken at intervals of only a few hours. This means we can track everything from intense but brief events, such as sudden downpours leading to flash flooding, to the slow variability and change that occurs over centuries. In 2020, colleagues and I started a not-for-profit called Open Data Rescue, with a mandate to locate, transcribe and analyze these historical weather and climate records. With support from Environment and Climate Change Canada, we found records of Canadian weather and climate from 50 locations in archival sources outside of Canada, mainly from the National Archives and Records Administration and National Centre for Environmental Information in the United States and the Meteorological Office Library and Archives in the United Kingdom. Our research A logbook from the McGill Observatory established by meteorologist Charles Smallwood in 1863 in Montréal. (DRAW Project), Author provided (no reuse) We faced a host of…