Climate Trends and Variations Bulletin – Summer 2018

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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 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 hiatus pending the extensive data reconciliation, and resumed 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.

National temperature

The national average temperature for the summer (June–August) of 2018 was 0.7°C above the baseline average (defined as the mean over the 1961–1990 reference period), based on preliminary data, which is the 21st 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 parts of British Columbia, Ontario, and Quebec experienced temperatures notably above the baseline average. Summer temperatures were generally near the baseline average in the remainder of the country.

Temperature departures from the 1961–1990 average – Summer 2018

The temperature departures map.
Long description 

The temperature departures map shows that parts of British Columbia, Ontario, and Quebec experienced temperatures notably above the baseline average. Summer temperatures were generally near the baseline average in the remainder of the country.

The time series graph (below) shows that averaged summer temperatures across the country have fluctuated from year to year over the 1948–2018 period. The linear trend indicates that summer temperatures averaged across the nation have warmed by 1.5°C over the past 71 years.

Summer national temperature departures and long-term trend, 1948–2018

The time series graph shows that averaged summer temperatures across the country have fluctuated from year to year.
Long description 

The time series graph shows that averaged summer temperatures across the country have fluctuated from year to year over the 1948–2018 period. The linear trend indicates that summer temperatures averaged across the nation have warmed by 1.5°C over the past 71 years.

Regional temperature

When examined on a regional basis, average summer temperatures for 2018 were among the 10 warmest on record since 1948 for three of the eleven climate regions: Atlantic Canada (10th warmest at 1.0°C above average), Great Lakes/St. Lawrence (9th warmest at 1.3°C above average) and the Pacific Coast (10th warmest at 1.2°C above average). None of the eleven climate regions experienced an average summer temperature for 2018 that ranked among the 10 coldest since 1948.  All eleven climate regions exhibit positive trends for summer temperatures over the 71 years of record. The strongest trend is observed in the Mackenzie District region (+1.9°C), while the weakest trend (+1.0°C) is found in the Prairies region. A table listing the regional and national temperature departures and rankings from 1948 to 2018 and a table that summarizes regional and national trends and extremes summaries are available on request to ec.btvc-ctvb.ec@canada.ca.

A map that shows the Canadian climate regions.
Long description

A map that shows the Canadian Climate Regions: Atlantic Canada, Great Lakes/St. Lawrence Lowlands, Northeastern Forest, Northwestern Forest, Prairies, South British Columbia Mountains, Pacific Coast, North British Columbia Mountains/Yukon, Mackenzie District, Arctic Tundra, Arctic Mountains and Fiords.

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