Animating Canada’s Climate History

(Click image to enlarge)

This animated map shows Canada’s changing climate using weather station data going all the way back to 1898.

Through much of the 20th century, the map shows a mixture of red dots (warmer than average) and grey dots (colder than average). Year-to-year fluctuations and regional differences are a normal part of a healthy climate system. Here, however, we see an obvious trend from cooler to warmer temperatures, a clear symptom of planetary warming. In the last 20 years, the map remains almost entirely red.

In a previous post, we used a simple graphic to illustrate this Canada-wide warming trend. This map revisits the same data, but shows that the warming can be seen on the ground, from coast to coast to coast, at the scale of individual weather stations, and not just in the abstract form of countrywide averages.

What does this map show?

  1. All of Canada is warming.
  2. The warming trend began decades ago.
  3. Most years have been warmer than average since the mid 1970s.
  4. All of the past 20 years have been above average. 

How do we know Canada is warming because of human-caused climate change?

We wrote a post reviewing the evidence that shows  human activity is causing climate change. Check it out now in case you missed it!

Ryan Smith & Steve McCullough

Prairie Climate Centre

The Prairie Climate Centre is committed to making climate change meaningful and relevant to Canadians. We explain and communicate climate change through maps, videos, reports, and web content like this. Sign up for our mailing list to stay informed about our work and about new developments in climate change science and policy. Help us move Canada from climate risk to resilience.

Data & Methods

Each dot on the map shows how much warmer or colder a weather station was compared to its 20th century average temperature. Red dots are warmer than average, grey dots are colder than average, and . the size and colour of the dot reflects how much warmer or colder that station’s measurements were for the year. Large dark red dots, for instance, were much warmer.

The inset graph shows the country-wide year-by-year temperature difference (in °C) for comparison and context.

This map was creating using observed mean temperature data from Environment and Climate Change Canada. The annual temperature anomalies for each station were computed using a 1901-2000 baseline period. Importantly, the number of stations actively logging data changes over this time period. Click here to see a graph showing the number of stations reporting per year.

The federal “Historical Climate Data” archive contains observations going back as far as 1840. Scientists have used this data to produce a high-quality historical record of monthly averages that describe Canada’s climate. We start with 1898 because there was no Arctic data available before this year.