Climate Trends and Variations Bulletin - Summer 2021

Summer 2021 bulletin (PDF, 1.4 MB)

This bulletin summarizes recent climate data and presents it in a historical context. It first examines the national average temperature for the season and then highlights interesting regional temperature information.

Over the past decade, precipitation monitoring technology has evolved and Environment and Climate Change Canada (ECCC) and its partners implemented a transition from manual observations to using automatic precipitation gauges. Extensive data integration is required to link the current precipitation observations to the long term historical manual observations. The update and reporting of historical adjusted precipitation trends and variations will be on temporary hiatus pending the extensive data reconciliation, and will resume thereafter. ECCC remains committed to providing credible climate data to inform adaptation decision making, while ensuring the necessary data reconciliation occurs as monitoring technology evolves.

Temperature departures and rankings data table (CSV, 9 kB) 
Temperature trends and extremes data table (CSV, 2 kB)

National temperature

The national average temperature for the summer (June–August) of 2021 was 1.3°C above the baseline average (defined as the mean over the 1961–1990 reference period), based on preliminary data, which is the 5^th warmest observed since nationwide recording began in 1948. The warmest summer occurred in 2012, when the national average temperature was 1.8°C above the baseline average. The coldest summer occurred in 1978, when the national average temperature was 1.0°C below the baseline average. The temperature departures map (below) shows that most of Canada experienced temperatures at least 1.0°C above the baseline average. Central and southern British Columbia experienced temperatures more than 2.5°C above the baseline average. Only the central region of Nunavut and northern Quebec experienced summer temperatures near the baseline average.

Temperature departures from the 1961 to 1990 average - Summer 2021

The time series graph (below) shows that averaged summer temperatures across the country have fluctuated from year to year over the 1948–2021 period. With the exception of 2004, averaged summer temperatures have remained above the baseline average since 1993. The linear trend indicates that summer temperatures averaged across the nation have warmed by 1.5°C over the past 74 years.

Summer National Temperature Departures and Long-term Trend, 1948–2021  

Regional temperature

When examined on a regional basis, average summer temperatures for 2021 were among the 10 warmest on record since 1948 for eight of the eleven climate regions. The South B.C. Mountains experienced its warmest summer (at 2.4°C above the baseline average); the regions which had their 2^nd warmest summer were the Prairies (at 2.0°C above the baseline average) and the Northwestern Forest (at 1.6°C above the baseline average); the regions with their 3^rd warmest summers were the Great Lakes / St. Lawrence (at 1.9°C above the baseline average) and Atlantic Canada (at 1.4°C above the baseline average); the Pacific Coast experienced its 4^th warmest summer (at 1.9°C above the baseline average); the Northeastern Forest had its 5^th warmest summer (at 1.6°C above the baseline average) and the Yukon/North B.C. Mountain had this summer ranked 6^th warmest (at 1.5°C above the baseline average). None of the eleven climate regions experienced an average summer temperature for 2021 that ranked among the 10 coolest since 1948. All eleven climate regions exhibit positive trends for summer temperatures over the 74 years of record. The strongest trend is observed in the Mackenzie District (+1.8°C), while the weakest trend (+1.1°C) is found in the Prairies region. Tables listing the Summer regional and national temperature departures and rankings from 1948 to 2021 (CSV, 9kB) and summarizing the Summer regional and national trends and extremes (CSV, 2kB) are available through the above links or by request to btvc-ctvb@ec.gc.ca.

Please note that the latest generation of CANGRD is now adopted in the analyses of the Climate Trends and Variations Bulletin (CTVB). For more information, please visit: About CTVB.

The map of Canadian Climate Regions