Digitization of centuries of Canadian weather records promises to improve climate understanding | Newsroom - McGill University
Offline
Error loading page resources
Please try to reload the page to display it correctly. For more information, see this article.
'>
McGill University
Fr
Newsroom
Institutional Communications
Enter your keywords
Main navigation
Home<br>For journalists<br>For faculty and staff<br>Experts guide<br>About us<br>Contact us
Home
News
Digitization of centuries of Canadian weather records promises to improve climate understanding
McGill-affiliated project drew on handwritten records dating from 1768 to 1884 that detail temperature, precipitation, wind, storms and more
Published: 18 June 2026
Tweet Widget
Researchers have uncovered and digitized nearly two million 18th and 19th century weather observations from across Canada that offer new insights into how the country’s climate has changed over time.
The international project draws on handwritten records dating from 1768 to 1884. The data include temperature, precipitation, wind and detailed descriptions of such events as storms and floods.
“The paper is a data study, so in that sense we were looking for, documenting and transcribing meteorological observations from overseas archives, given Canada’s colonial history,” said Victoria Slonosky, an afiiliated researcher in the Department of Geography and lead author of a recent study in Scientific Data.
To build the dataset, researchers obtained fragile documents digitized by archives, transcribed the observations into a database and converted the measurements into modern units. Slonosky also helped establish Open Data Rescue, a not-for-profit organization that supports the search and transcription of Canadian weather records, along with related efforts such as McGill’s DRAW (Data Rescue: Archives and Weather) project.
Researchers drew on military and medical weather logs held in the United Kingdom’s Meteorological Office archives and records at the U.S. National Archives, including observations by Hudson’s Bay Company employees and missionaries.
Rich detail from the past
One surprise was the level of detail: Observers often recorded conditions two or three times a day and noted far more than temperature.
“As well as thermometer observations, there are wind, cloud, rain, snow, atmospheric humidity and atmospheric pressure observations, along with descriptions of the weather and sky,” Slonosky said.
These accounts include descriptions of floods, fires, storms and aurora, allowing researchers to identify past extreme events.
Filling a major knowledge gap
Until now, much of Canada’s early weather record was poorly understood, especially pertaining to northern and western regions.
“There was a ‘fog of ignorance’ … for this area,” Slonosky said, noting that limited data has made it harder to understand how storms form and evolve over time.
The newly digitized records suggest the climate in this period, near the end of the Little Ice Age, was highly variable.
“We knew it was generally colder than today, but discovering such a wealth of information also helps us see that the weather was more variable than in the 20th century generally,” she said.
Understanding how disruptive weather events happen
Researchers say the findings will help improve understanding of extreme weather events that affect people now and may also help put today’s climate headlines in context.
“We see the word ‘unprecedented’ a lot … so we’d like to find out if some of these things really are unprecedented, or if we just have short records and shorter memories,” Slonosky said.
About the study
Transcribing historical Canadian weather data by Victoria Slonosky et al. was published in Nature’s Scientific Data. It was funded by Environment and Climate Change Canada.
Contact Information
Contact:<br>Claire Loewen
Organization:<br>Communications Officer, Science and Engineering
Email:<br>claire.loewen [at] mcgill.ca
Category:<br>News releases
Last updated:<br>Thu, 06/18/2026 - 09:07
Source Site:<br>/newsroom
Related Content
News
Study offers new insights into why ex-smokers remain at elevated risk of lung disease<br>Published: 22 Jul 2026
Green LED light could help keep leafy greens fresher longer, McGill study suggests<br>Published: 22 Jul 2026
CHIME collaboration helps identify location of "missing" matter in the universe<br>Published: 21 Jul 2026
View more news
Experts
Experts: New U.S. tariffs on Canadian goods<br>Published: 21 Jul 2026
Expert: Bank of Canada’s interest rate announcement<br>Published: 14 Jul 2026
Experts: Cyclosporiasis outbreak<br>Published: 13 Jul 2026
Experts: Royal Canadian Navy's new fleet of submarines<br>Published: 6 Jul 2026
Experts: Summer stresses on families<br>Published: 2 Jul 2026
View more news
Back to top
Department and University Information
Institutional Communications
James Administration Building
845 Sherbrooke Street West
Montréal, Québec H3A 0G4
514-398-6693
Contact...