Climate Trends and Variations Bulletin – Autumn 2017

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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 temporary 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 autumn (September-November) of 2017 was 1.2°C above the baseline average (defined as the mean over the 1961–1990 reference period), based on preliminary data, which is the 19th warmest observed since nationwide recording began in 1948. The warmest autumn occurred in 1998, when the national average temperature was 2.5°C above the baseline average. The coldest autumn occurred in 1972, when the national average temperature was 1.8°C below the baseline average. The temperature departures map (below) shows that much of northern and eastern Canada experienced temperatures above the baseline average, while areas of the Yukon, British Columbia, Alberta, and Saskatchewan experienced temperatures below the baseline average. Autumn temperatures were near the baseline average in the remainder of the country.

 Temperature departures from the 1961–1990 average – Autumn 2017

The temperature departures map.
Long description 

The temperature departures map shows that much of northern and eastern Canada experienced temperatures above the baseline average, while areas of the Yukon, British Columbia, Alberta, and Saskatchewan experienced temperatures below the baseline average. Autumn temperatures were near the baseline average in the remainder of the country.

The time series graph (below) shows that averaged autumn temperatures across the country have fluctuated from year to year over the 1948–2017 period. The linear trend indicates that autumn temperatures averaged across the nation have warmed by 1.7°C over the past 70 years.

Autumn national temperature departures and long-term trend, 1948–2017

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

The time series graph shows that averaged autumn temperatures across the country have fluctuated from year to year over the 1948–2017 period. The linear trend indicates that autumn temperatures averaged across the nation have warmed by 1.7°C over the past 70 years.

Regional temperature

When examined on a regional basis, average autumn temperatures for 2017 were among the 10 warmest on record since 1948 for three of the eleven climate regions: Atlantic Canada (7th warmest at 1.6°C above average), the Great Lakes/St. Lawrence region (8th warmest at 1.7°C above average) and the Arctic Tundra region (10th warmest at 2.3°C above average). None of the eleven climate regions experienced an average autumn temperature for 2017 that ranked among the 10 coldest since 1948. All eleven climate regions exhibit positive trends for autumn temperatures over the 70 years of record. The strongest regional trend (+2.6°C) is observed in the Arctic Tundra region, while the weakest trend (+0.6°C) is found in the South B.C. Mountains region. A table listing the regional and national temperature departures and rankings from 1948 to 2017 and a table that summaries 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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